Search results for: number of defects
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 10515

Search results for: number of defects

8805 Correction of Urinary Incontinence in Severe Spinal Canal Stenosis, Treated Patients

Authors: Ilirian Laçi, Alketa Spahiu

Abstract:

Ageing causes an increase in the number of patients with spinal canal stenosis. Most of the patients have back pain, leg pain, numbness of the legs, as well as urinary incontinence as a very common symptoms. Urinary incontinence impairs the quality of life. Correction of the symptom of urinary incontinence is possible in the early and adequate treatment of spinal stenosis. Methods: This study observed patients with urinary incontinence and spinal canal stenosis. These patients underwent mechanical decompression of the spinal stenosis through surgery. At the same time, these patients were observed clinically with clinical consultations. Cystoscopy and urodynamic tests were conducted at intervals of 2 and 6 months. As a result of treatment, 60% of patients did recover. The patients in this group who benefit from treatment were the patients who were early diagnosed and treated. Conclusions: An important factor in the prognosis of this pathology is the early diagnosis and treatment. The proper treatment of this pathology makes it curable in most cases. An important role in this pathology is played by the neurosurgeon. Surgery accompanied by laminotomy and mechanical decompression is the best way of treatment. Other factors that played a role in this pathology are also a large number of childbirths for women, obesity, etc.

Keywords: urinary incontinence, quality of life, spinal canal stenosis, early diagnosis, treatment

Procedia PDF Downloads 96
8804 Technical Efficiency of Small-Scale Honey Producer in Ethiopia: A Stochastic Frontier Analysis

Authors: Kaleb Shiferaw, Berhanu Geberemedhin

Abstract:

Ethiopian farmers have a long tradition of beekeeping and the country has huge potential for honey production. However traditional mode of production still dominates the sub sector which negatively affect the total production and productivity. A number of studies have been conducted to better understand the working honey production, however, none of them systematically investigate the extent of technical efficiency of the sub-sector. This paper uses Stochastic Frontier production model to quantifying the extent of technical efficiency and identify exogenous determinant of inefficiency. The result showed that consistent with other studies traditional practice dominate small scale honey production in Ethiopia. The finding also revealed that use of purchased inputs such as bee forage and other supplement is very limited among honey producers indicating that natural bee forage is the primary source of bee forage. The immediate consequence of all these is low production and productivity. The number of hives the household owns, whether the household used improved apiculture technologies, availability of natural forest which is the primary sources of nectar for bees and amount of land owned by the households were found to have a significant influence on the amount of honey produced by beekeeper. Our result further showed that the mean technical efficiency of honey producers is 0.79 implying that, on average honey producer produce 80 percent of the maximum output. The implication is that 20 percent of the potential output is lost due to technical inefficiency. Number of hives owned by a honey produces, distance to district town-a proxy to market access, household wealth, and whether the household head has a leadership role in the PA affect the technical efficiency of honey producers. The finding suggest that policies that aim to expand the use of improved hives is expected to increase the honey production at household level. The result also suggest that investment on rural infrastructure would be instrumental in improving technical efficiency of honey producer.

Keywords: small-scale honey producer, Ethiopia, technical efficiency in apiculture, stochastic frontier analysis

Procedia PDF Downloads 230
8803 Analyzing Competition in Public Construction Projects

Authors: Khaled Hesham Hyari, Amjad Almani

Abstract:

Construction projects in the public sector are commonly awarded through competitive bidding. In the last decade, the Construction projects environment in the Middle East went through many changes. These changes have been caused by different factors including the economic crisis, delays in monthly payments, international competition and reduced number of projects. These factors had a great impact on the bidding behaviors of contractors and their pricing strategies. This paper examines the competition characteristics in public construction projects through an analysis of bidding results of contractors in public construction projects over a period of 6 years (2006-2011) in Jordan. The analyzed projects include all categories of projects such as infrastructure, buildings, transportation and engineering services (design and supervision contracts). Data for the projects were obtained from the General Tender’s Directorate in Jordan and includes 462 projects. The analysis performed in this projects includes, studying the bid spread in all projects as it is an indication of the level of competition in the analyzed bids. The analysis studied the factors that affect bid spread such as number of bidders, Value of the project, Project category and years. It also studying the “Signal to Noise Ratio” in all projects as it is an indication of the accuracy of cost estimating performed by competing bidders and bidder´s evaluation of project risks. The analysis performed includes the relationship between signal to noise ratio and different parameters such as project category, number of bidders and changes over years. Moreover, the analysis includes determining the bidder´s aggressiveness in bidding as it is an indication of competition level in such projects. This was performed by determining the pack price which can be considered as the true value of the project and comparing it with the lowest bid submitted for each project to determine the level of aggressiveness in submitted bids. The analysis performed in this project should prove to be useful to owners in understanding bidding behaviors of contractors and pointing out areas that needs improvement in preparing bidding documents. Also the project should be useful to contractors in understanding the competitive bidding environment and should help them to improve their bidding strategies to maximize the success rate in obtaining contracts.

Keywords: construction projects, competitive bidding, public construction, competition

Procedia PDF Downloads 328
8802 Ceramic Glazes from Recycled Bottle Glass

Authors: Suraphan Rattanavadi

Abstract:

This research was a study based on an application of used glass in producing glaze on ceramics. The aim was to identify the factors in the production process that affected ceramic product property when used glass was applied as the ceramic glaze. The study factors included appropriate materials, appropriate temperature used in fusion process, percentage of water absorption, fluidity, crazing and appropriate proportion in glaze production by Biaxial Blend Technique and use of oxide in glaze coloring both on test and real product. The test of fluidity revealed that the glazes number 15 and 16 had appropriate fluidity ratio for use as basic glaze. When each glaze was mixed with oxide at different proportion, it was discovered that the glaze number 16 showed glossy brown with beautiful but not clear crazing, due to its dark shade. This was from the mixture of kaolin and pieces of glass at the ratio of 1:3 (kaolin : pieces of glass), affecting at 10% with iron oxide. When 0.5% of copper carbonate and 0.1% of tin oxide were added, the result was the glaze with glossy, Muzo emerald (green- blue) color with beautiful and clear crazing. Lastly, 0.4% of cobalt carbonate was added, ending in the glaze with glossy, bright blue with beautiful but not clear, due to its dark shade.

Keywords: glaze, recycled, bottle glass, ceramic

Procedia PDF Downloads 302
8801 Highly Efficient in Vitro Regeneration of Swertia chirayita (Roxb. ex Fleming) Karsten: A Critically Endangered Medicinal Plant

Authors: Mahendran Ganesan, Sanjeet Kumar Verma, Zafar Iqbal, Ashish Chandran, Zakir Husain, Shama Afroz, Sana Shahid, Laiq Ur Rahman

Abstract:

Highly efficient in vitro regeneration system has been developed for Swertia chirayita (Roxb. ex Fleming) H. Karst, a high prized traditional medicinal plant to treat numerous ailments such as liver disorders, malaria and diabetes and are reported to have a wide spectrum of pharmacological properties. Its medicinal usage is well-documented in Indian pharmaceutical codex, the British and the American pharmacopeias, and in different traditional medicine such as the Ayurveda, Unani and Siddha medical systems. Nodal explants were cultured on MS medium supplemented with various phytohormones for multiple shoot induction. The nodal segments failed to respond in growth regulator free medium. All the concentrations of BAP, Kin and TDZ facilitated shoot bud break and multiple shoot induction. Among the various cytokinins tested, BAP was found to be more effective with respect to initiation and subsequent development of shoots. Of the various concentrations BAP tested, BAP at 4.0 mg/L showed the higher average number of shoot regeneration (10.80 shoots per explant). Kin at 4 mg/L and TDZ at 4 mg/L induced 5.70 and 04.5+0 shoots per explant, respectively. Further increase in concentration did not favour an increase in the number of shoots. However, these shoots failed to elongate further. Hence, addition of GA₃ (1 mg/L) was added to the above medium. This treatment resulted in the elongation of shoots (2.50 cm) and a further increase in the number of microshoots (34.20 shoots/explant). Roots were also induced in the same medium containing BAP (4 mg/L) + GA₃ (1 mg/L) + NAA (0.5 mg/L). In vitro derived plantlets with well-developed roots were transferred to the potting media containing garden soil: sand: vermicompost (2:1:1). Plantlets were covered with a polyethylene bag and irrigated with water. The pots were maintained at 25 ± 2ºC, and then the polyethylene cover was gradually loosened, thus dropping the humidity (65–70%). This procedure subsequently resulted in in vitro hardening of the plantlet.

Keywords: micropropagation, nodal explant, plant growth regulators, Swertia chirayita

Procedia PDF Downloads 114
8800 Multiple Shoot Induction and Plant Regeneration of Kepuh (Sterculia foetida L.) Tissue Culture

Authors: Titin Handayani, Endang Yuniastuti

Abstract:

Kepuh (Sterculia foetida L.) is a potential plant contain mainly oil seeds that can be used as a source of alternative bioenergy and medicine. The main problem of kepuh cultivation is the limited supply of seed plants. Seeds development were very easy, but to produce fruit have to wait for approximately 5 years. The objective of this research was to obtain kepuh plants through direct in vitro regeneration. Hypocotyls and shoot tips explants were excised from sterile germinated seedlings and placed on shoot induction medium containing basal salts of Murashige and Skoog (MS) and various concentrations of plant growth regulators. The results showed that shoots induction from the apical and axillary buds on MS medium + 1.5 and 2 mg/L BAP and 0.5 and 1 mg/L IAA was growth very slowly. Increasing of BAP concentrations was increased shoot formation. The first subcultures were increased the rate of shoots growth on MS medium supplemented with 2 mg/L BAP and 0.5 mg/L IAA. The second of shoots subculture on MS medium + 1.5 to 2 mg/L BAP + 0.5 mg/L IAA was increased the number of shoots up to 4.8 in average. The best medium of shoots elongation were MS + 1 mgL-1 kinetin + 5 mg/L GA3. The highest percentage of roots (65%) occurred on MS medium with 5 mg/L IBA which average number of roots was 3.1. High percentages of survival and plants of normal appearance were obtained after five weeks of acclimatization.

Keywords: Kepuh, Sterculia foetida L, shoot multiplication, rooting, acclimatization, bioenergy, medicine

Procedia PDF Downloads 290
8799 An Efficient Hardware/Software Workflow for Multi-Cores Simulink Applications

Authors: Asma Rebaya, Kaouther Gasmi, Imen Amari, Salem Hasnaoui

Abstract:

Over these last years, applications such as telecommunications, signal processing, digital communication with advanced features (Multi-antenna, equalization..) witness a rapid evaluation accompanied with an increase of user exigencies in terms of latency, the power of computation… To satisfy these requirements, the use of hardware/software systems is a common solution; where hardware is composed of multi-cores and software is represented by models of computation, synchronous data flow (SDF) graph for instance. Otherwise, the most of the embedded system designers utilize Simulink for modeling. The issue is how to simplify the c code generation, for a multi-cores platform, of an application modeled by Simulink. To overcome this problem, we propose a workflow allowing an automatic transformation from the Simulink model to the SDF graph and providing an efficient schedule permitting to optimize the number of cores and to minimize latency. This workflow goes from a Simulink application and a hardware architecture described by IP.XACT language. Based on the synchronous and hierarchical behavior of both models, the Simulink block diagram is automatically transformed into an SDF graph. Once this process is successfully achieved, the scheduler calculates the optimal cores’ number needful by minimizing the maximum density of the whole application. Then, a core is chosen to execute a specific graph task in a specific order and, subsequently, a compatible C code is generated. In order to perform this proposal, we extend Preesm, a rapid prototyping tool, to take the Simulink model as entry input and to support the optimal schedule. Afterward, we compared our results to this tool results, using a simple illustrative application. The comparison shows that our results strictly dominate the Preesm results in terms of number of cores and latency. In fact, if Preesm needs m processors and latency L, our workflow need processors and latency L'< L.

Keywords: hardware/software system, latency, modeling, multi-cores platform, scheduler, SDF graph, Simulink model, workflow

Procedia PDF Downloads 260
8798 Application of Ground Penetrating Radar and Light Falling Weight Deflectometer in Ballast Quality Assessment

Authors: S. Cafiso, B. Capace, A. Di Graziano, C. D’Agostino

Abstract:

Systematic monitoring of the trackbed is necessary to assure safety and quality of service in the railway system. Moreover, to produce effective management of the maintenance treatments, the assessment of bearing capacity of the railway trackbed must include ballast, sub-ballast and subgrade layers at different depths. Consequently, there is an increasing interest in obtaining a consistent measure of ballast bearing capacity with no destructive tests (NDTs) able to work in the physical and time restrictions of railway tracks in operation. Moreover, in the case of the local railway with reduced gauge, the use of the traditional high-speed track monitoring systems is not feasible. In that framework, this paper presents results from in site investigation carried out on ballast and sleepers with Ground Penetrating Radar (GPR) and Light Falling Weight Deflectometer (LWD). These equipment are currently used in road pavement maintenance where they have shown their reliability and effectiveness. Application of such Non-Destructive Tests in railway maintenance is promising but in the early stage of the investigation. More specifically, LWD was used to estimate the stiffness of ballast and sleeper support, as well. LWD, despite the limited load (6 kN in the trial test) applied directly on the sleeper, was able to detect defects in the bearing capacity at the Sleeper/Ballast interface. A dual frequency GPR was applied to detect the presence of layers’ discontinuities at different depths due to fouling phenomena that are the main causes of changing in the layer dielectric proprieties within the ballast thickness. The frequency of 2000Mhz provided high-resolution data to approximately 0.4m depth, while frequency of 600Mhz showed greater depth penetration up to 1.5 m. In the paper literature review and trial in site experience are used to identify Strengths, Weaknesses, Opportunities, and Threats (SWOT analysis) of the application of GPR and LWD for the assessment of bearing capacity of railway track-bed.

Keywords: bearing capacity, GPR, LWD, no destructive test, railway track

Procedia PDF Downloads 125
8797 Identification of a Print Design Approach for the Application of Multicolour and Pattern Changing Effects

Authors: Dilusha Rajapakse

Abstract:

The main reason for printing coloured imageries, pattern or motif onto textiles is to enhance the visual appearance of the surface so that the final textile product would get the required attention from potential customers. Such colours and patterns are permanently applied onto the textiles using conventional static colourants, and we expect such decorations to be last for the entire lifecycle of the textile product. The focus of this research presentation is to discuss the ability to integrate multicolour and pattern changing aesthetics onto textiles with the application of water based photochromic colourants. By adopting a research through design approach, a number of iterative flatbed screen printing experiments were conducted to explore the process of printing water based photochromic colours on textile surfaces. The research resulted in several technical parameters that have to be considered during the process of screen printing. Moreover, a modified printing technique that could be used to apply decorative photographic imagery onto textile with multicolour changing effects was also identified. A number of product applications for such dynamic printed textiles were revealed, and appropriate visual evidence was referred to justify the finding.

Keywords: dynamic aesthetics, multicolour changing textiles, non-emissive colours, printed textile design

Procedia PDF Downloads 387
8796 Method and Apparatus for Optimized Job Scheduling in the High-Performance Computing Cloud Environment

Authors: Subodh Kumar, Amit Varde

Abstract:

Typical on-premises high-performance computing (HPC) environments consist of a fixed number and a fixed set of computing hardware. During the design of the HPC environment, the hardware components, including but not limited to CPU, Memory, GPU, and networking, are carefully chosen from select vendors for optimal performance. High capital cost for building the environment is a prime factor influencing the design environment. A class of software called “Job Schedulers” are critical to maximizing these resources and running multiple workloads to extract the maximum value for the high capital cost. In principle, schedulers work by preventing workloads and users from monopolizing the finite hardware resources by queuing jobs in a workload. A cloud-based HPC environment does not have the limitations of fixed (type of and quantity of) hardware resources. In theory, users and workloads could spin up any number and type of hardware resource. This paper discusses the limitations of using traditional scheduling algorithms for cloud-based HPC workloads. It proposes a new set of features, called “HPC optimizers,” for maximizing the benefits of the elasticity and scalability of the cloud with the goal of cost-performance optimization of the workload.

Keywords: high performance computing, HPC, cloud computing, optimization, schedulers

Procedia PDF Downloads 82
8795 The Influence of Polymorphisms of NER System Genes on the Risk of Colorectal Cancer in the Polish Population

Authors: Ireneusz Majsterek, Karolina Przybylowska, Lukasz Dziki, Adam Dziki, Jacek Kabzinski

Abstract:

Colorectal cancer (CRC) is one of the deadliest cancers. Every year we see an increase in the number of cases, and in spite of intensive research etiology of the disease remains unknown. For many years, researchers are seeking to associate genetic factors with an increased risk of CRC, so far it has proved to be a compelling link between the MMR system of DNA repair and hereditary nonpolyposis colorectal cancers (HNPCC). Currently, research is focused on finding the relationship between the remaining DNA repair systems and an increased risk of developing colorectal cancer. The aim of the study was to determine the relationship between gene polymorphisms Ser835Ser of XPF gene and Gly23Ala of XPA gene–elements of NER DNA repair system, and modulation of the risk of colorectal cancer in the Polish population. Determination of the molecular basis of carcinogenesis process and predicting increased risk will allow qualifying patients to increased risk group and including them in preventive program. We used blood collected from 110 patients diagnosed with colorectal cancer. The control group consisted of equal number of healthy people. Genotyping was performed by TaqMan method. The obtained results indicate that the genotype 23Gly/Ala of XPA gene is associated with an increased risk of colorectal cancer, while 23Ala/Ala as well as TCT allele of Ser835Ser of XPF gene may reduce the risk of CRC.

Keywords: NER, colorectal cancer, XPA, XPF, polymorphisms

Procedia PDF Downloads 563
8794 Attribute Analysis of Quick Response Code Payment Users Using Discriminant Non-negative Matrix Factorization

Authors: Hironori Karachi, Haruka Yamashita

Abstract:

Recently, the system of quick response (QR) code is getting popular. Many companies introduce new QR code payment services and the services are competing with each other to increase the number of users. For increasing the number of users, we should grasp the difference of feature of the demographic information, usage information, and value of users between services. In this study, we conduct an analysis of real-world data provided by Nomura Research Institute including the demographic data of users and information of users’ usages of two services; LINE Pay, and PayPay. For analyzing such data and interpret the feature of them, Nonnegative Matrix Factorization (NMF) is widely used; however, in case of the target data, there is a problem of the missing data. EM-algorithm NMF (EMNMF) to complete unknown values for understanding the feature of the given data presented by matrix shape. Moreover, for comparing the result of the NMF analysis of two matrices, there is Discriminant NMF (DNMF) shows the difference of users features between two matrices. In this study, we combine EMNMF and DNMF and also analyze the target data. As the interpretation, we show the difference of the features of users between LINE Pay and Paypay.

Keywords: data science, non-negative matrix factorization, missing data, quality of services

Procedia PDF Downloads 124
8793 Effects of Drought Stress on Red Bean (Phaseolus vulgaris L.) Cultivars during Post-Flowering Growth Stage

Authors: Fariborz Shekari, Abdollah Javanmard, Amin Abbasi

Abstract:

A pot experiment conducted to evaluate the response of two red bean cultivars, Sayad and Derakhshan, to water deficit stress during post-flowering growth stage and recovery potential of plants after stress. Treatments were included regular irrigation or control, water deficit during flowering stage, water deficit during pod formation and water deficit during pod filling period. Results showed that plant height had positive effects on yield of cultivars so that, the tall cultivar, ‘Sayad’, had higher yields. Stress application during flowering stage showed the highest negative impact on plant height and subsequently yield. The longest and the higher number of pods as well as the greatest number of seeds in pods were recorded in control treatment in ‘Sayad’. Stress application during pod formation resulted in the minimum amount of all studied traits in both cultivars. Stress encountered during seed filling period had the least effect on number and length of pods and seed/pod. However, 100 seeds weight significantly decreased. The highest amount for 100 seeds weight was record in control plants in ‘Derakhshan’. Under all treatments, ‘Sayad’ had higher biologic and seed yield compared to ‘Derakhshan’. The least amount of yield was recorded during stress application in pod formation and flowering period for ‘Sayad’ and ‘Derakhshan’ respectively. Harvest index of ‘Sayad’ was more affect by stress application. Data related to photosynthetic rate showed that during stress application, ‘Derakhshan’ owned rapid decline in photosynthesis. Beyond stress alleviation and onset of irrigation, recovery potential of ‘Sayad’ was higher than ‘Derakhshan’ and this cultivar was able to rapidly restore the photosynthesis rate of stress faced plants near control ones. In total, stress had lower impacts on photosynthetic rate of ‘Sayad’ cultivar.

Keywords: common bean, water stress, yield, yield components, photosynthetic rate

Procedia PDF Downloads 292
8792 Omalizumab Therapy Experience for Asthma, at Zayed Military Hospital (ZMH) in United Arab Emirates

Authors: Shanza Akram, Samir Salah, Imran Saleem, Ashraf Alzaabi, Jassim Abdou

Abstract:

Introduction: 300 million people worldwide are affected by asthma .In UAE, prevalence is around 10% (900,000 people).Patients with persistent symptoms despite using high dose ICS plus a second controller +/- OCS are considered to have severe asthma. Omalizumab (Xolaire) an IgE monoclonal antibody is approved as add on therapy for severe allergic asthma. Objective: To determine the efficacy of omalizumab based on clinical outcomes in our cohort of patient pre and post 52 weeks of treatment to assess safety and tolerability of treatment. Methods: Medical records of patients receiving omalizumab therapy for asthma at ZMH ,Abu Dhabi were retrospectively analyzed.Patients fulfilling the criteria of severe allergic asthma as per GINA guidelines were included. Asthma control over 12 months prior to and 12 months after commencement of omalizumab therapy was analysed by taking into account the number of exacerbations and hospitalizations in addition to maintenance of medication dosages, need for rescue reliever therapy and pulmonary function testing. Results: Total cohort of 21 patient (5 females), average age 41 years and av length of therapy 22 months were included. Seven patients (total 11/52%) managed to stop steroids on treatment while four were able to decrease the dosage. Mean exacerbation rate decreased from five/ year pre treatment to 1.36 while on treatment. Number of hospitalizations decreased from mean of two per year to 0.9 per year. Rescue reliever inhaler usage decreased from mean of 40 puffs to 15 puffs per week. 2 patients discontinued therapy, 1 due to lack of benefit (2 doses) and 2nd due to severe persistent side effects including local irritation, severe limb and joint pains after 6 months. Conclusion: Treatment with omalizumab showed effect in terms of reduced number of exacerbations, maintenance therapy and reliever medications. However, no improvement was seen in PFTs.There is room for improved documentation in terms of symptom recording and use of rescue medicationas as well as for better patient education and counselling in order to improve compliance.

Keywords: asthma, omalizumab, severe allergic asthma, UAE

Procedia PDF Downloads 289
8791 Reducing the Risk of Alcohol Relapse after Liver-Transplantation

Authors: Rebeca V. Tholen, Elaine Bundy

Abstract:

Background: Liver transplantation (LT) is considered the only curative treatment for end-stage liver disease Background: Liver transplantation (LT) is considered the only curative treatment for end-stage liver disease (ESLD). The effects of alcoholism can cause irreversible liver damage, cirrhosis and subsequent liver failure. Alcohol relapse after transplant occurs in 20-50% of patients and increases the risk for recurrent cirrhosis, organ rejection, and graft failure. Alcohol relapse after transplant has been identified as a problem among liver transplant recipients at a large urban academic transplant center in the United States. Transplantation will reverse the complications of ESLD, but it does not treat underlying alcoholism or reduce the risk of relapse after transplant. The purpose of this quality improvement project is to implement and evaluate the effectiveness of a High-Risk Alcoholism Relapse (HRAR) Scale to screen and identify patients at high-risk for alcohol relapse after receiving an LT. Methods: The HRAR Scale is a predictive tool designed to determine the severity of alcoholism and risk of relapse after transplant. The scale consists of three variables identified as having the highest predictive power for early relapse including, daily number of drinks, history of previous inpatient treatment for alcoholism, and the number of years of heavy drinking. All adult liver transplant recipients at a large urban transplant center were screened with the HRAR Scale prior to hospital discharge. A zero to two ordinal score is ranked for each variable, and the total score ranges from zero to six. High-risk scores are between three to six. Results: Descriptive statistics revealed 25 patients were newly transplanted and discharged from the hospital during an 8-week period. 40% of patients (n=10) were identified as being high-risk for relapse and 60% low-risk (n=15). The daily number of drinks were determined by alcohol content (1 drink = 15g of ethanol) and number of drinks per day. 60% of patients reported drinking 9-17 drinks per day, and 40% reported ≤ 9 drinks. 50% of high-risk patients reported drinking ≥ 25 years, 40% for 11-25 years, and 10% ≤ 11 years. For number of inpatient treatments for alcoholism, 50% received inpatient treatment one time, 20% ≥ 1, and 30% reported never receiving inpatient treatment. Findings reveal the importance and value of a validated screening tool as a more efficient method than other screening methods alone. Integration of a structured clinical tool will help guide the drinking history portion of the psychosocial assessment. Targeted interventions can be implemented for all high-risk patients. Conclusions: Our findings validate the effectiveness of utilizing the HRAR scale to screen and identify patients who are a high-risk for alcohol relapse post-LT. Recommendations to help maintain post-transplant sobriety include starting a transplant support group within the organization for all high-risk patients. (ESLD). The effects of alcoholism can cause irreversible liver damage, cirrhosis and subsequent liver failure. Alcohol relapse after transplant occurs in 20-50% of patients, and increases the risk for recurrent cirrhosis, organ rejection, and graft failure. Alcohol relapse after transplant has been identified as a problem among liver transplant recipients at a large urban academic transplant center in the United States. Transplantation will reverse the complications of ESLD, but it does not treat underlying alcoholism or reduce the risk of relapse after transplant. The purpose of this quality improvement project is to implement and evaluate the effectiveness of a High-Risk Alcoholism Relapse (HRAR) Scale to screen and identify patients at high-risk for alcohol relapse after receiving a LT. Methods: The HRAR Scale is a predictive tool designed to determine severity of alcoholism and risk of relapse after transplant. The scale consists of three variables identified as having the highest predictive power for early relapse including, daily number of drinks, history of previous inpatient treatment for alcoholism, and the number of years of heavy drinking. All adult liver transplant recipients at a large urban transplant center were screened with the HRAR Scale prior to hospital discharge. A zero to two ordinal score is ranked for each variable, and the total score ranges from zero to six. High-risk scores are between three to six. Results: Descriptive statistics revealed 25 patients were newly transplanted and discharged from the hospital during an 8-week period. 40% of patients (n=10) were identified as being high-risk for relapse and 60% low-risk (n=15). The daily number of drinks were determined by alcohol content (1 drink = 15g of ethanol) and number of drinks per day. 60% of patients reported drinking 9-17 drinks per day, and 40% reported ≤ 9 drinks. 50% of high-risk patients reported drinking ≥ 25 years, 40% for 11-25 years, and 10% ≤ 11 years. For number of inpatient treatments for alcoholism, 50% received inpatient treatment one time, 20% ≥ 1, and 30% reported never receiving inpatient treatment. Findings reveal the importance and value of a validated screening tool as a more efficient method than other screening methods alone. Integration of a structured clinical tool will help guide the drinking history portion of the psychosocial assessment. Targeted interventions can be implemented for all high-risk patients. Conclusions: Our findings validate the effectiveness of utilizing the HRAR scale to screen and identify patients who are a high-risk for alcohol relapse post-LT. Recommendations to help maintain post-transplant sobriety include starting a transplant support group within the organization for all high-risk patients.

Keywords: alcoholism, liver transplant, quality improvement, substance abuse

Procedia PDF Downloads 108
8790 Coastal Environment: Statistical Analysis and Geomorphic Impact on Urban Tourism in Lagos, Portugal

Authors: Magdalena Kuleta

Abstract:

Ponta de Piedade (37º05 ' N, 08º40 ' W) is an area located in the southern part of the Lagos municipality, which include an abrasive and accumulative type of coastline. It is the one of the main touristic destinations of the city. The dynamic development of the attractiveness of the coast, is related with the expansion of the new tourism infrastructure and urban tourism products. These products are: transportation, sightseeing and entertainment in the form of the boat trips. Each type of excursion refers to the different product. This progress brings also many risks associated primarily with landslides cliffs. Natural conditions affecting the coast, create a huge impact on the evolution of urban tourism management. Based on observation, statistical analysis and survey method, author compare the period of six years from 2012 to 2016 in terms of the number of tourists, number and diversity of attractions, most frequently dialled products and infrastructure changes in the city. Carried methodology is based on data belonging to Turismo Portugal and the tourist company Days of Adventure. Main result, is to indicate the essence of the income from coastal tourism into the city development and how does it influence on the marketing and promoting of urban tourism in Lagos.

Keywords: geomorphology of the coast in Lagos, market and promotion, quality of tourism service, urban tourism products

Procedia PDF Downloads 312
8789 Effect of Molecular Weight Distribution on Toughening Performance of Polybutadiene in Polystyrene

Authors: Mohamad Mohsen Yavarizadeh

Abstract:

Polystyrene (PS) and related homopolymers are brittle materials that typically fail in tensile tests at very low strains. These polymers can be toughened by the addition of rubbery particles which initiate a large number of crazes that produce substantial plastic strain at relatively low stresses. Considerable energy is dissipated in the formation of these crazes, producing a relatively tough material that shows an impact toughness of more than 5 times of pure PS. While cross linking of rubbery phase is necessary in aforementioned mechanism of toughening, another mechanism of toughening was also introduced in which low molecular weight liquid rubbers can also toughen PS when dispersed in the form of small pools in the glassy matrix without any cross linking. However, this new mechanism which is based on local plasticization, fails to act properly at high strain rate deformations, i.e. impact tests. In this work, the idea of combination of these two mechanisms was tried. To do so, Polybutadiene rubbers (PB) with bimodal distribution of molecular weight were prepared in which, comparable fractions of very high and very low molecular weight rubbers were mixed. Incorporation of these materials in PS matrix in a reactive process resulted in more significant increases in toughness of PS. In other words, although low molecular weight PB is ineffective in high strain rate impact test by itself, it showed a significant synergistic effect when combined with high molecular weight PB. Surprisingly, incorporation of just 10% of low molecular weight PB doubled the impact toughness of regular high impact PS (HIPS). It was observed that most of rubbery particles could initiate crazes. The effectiveness of low molecular weight PB in impact test was attributed to low strain rate deformation of each individual craze as a result of producing a large number of crazes in this material. In other words, high molecular weight PB chains make it possible to have an appropriate dispersion of rubbery phase in order to create a large number of crazes in the PS matrix and consequently decrease the velocity of each craze. Low molecular weight PB, in turn, would have enough time to locally plasticize craze fibrils and enhance the energy dissipation.

Keywords: molecular weight distribution, polystyrene, toughness, homopolymer

Procedia PDF Downloads 438
8788 State of Play of Mobile Government Apps on Google Play Store

Authors: Abdelbaset Rabaiah

Abstract:

e-Government mobile applications provide an extension for effective e-government services in today’s omniconnected world. They constitute part of m-government platforms. This study explores the usefulness, availability, discoverability and maturity of such applications. While this study impacts theory by addressing a relatively lacking area, it impacts practice more. The outcomes of this study suggest valuable recommendations for practitioners-developers of e-government applications. The methodology followed is to examine a large number of e-government smartphone applications. The focus is on applications available at the Google Play Store. Moreover, the study investigates applications published on government portals of a number of countries. A sample of 15 countries is researched. The results show a diversity in the level of discoverability, development, maturity, and usage of smartphone apps dedicated for use of e-government services. It was found that there are major issues in discovering e-government applications on both the Google Play Store and as-well-as on local government portals. The study found that only a fraction of mobile government applications was published on the Play Store. Only 19% of apps were multilingual, and 43% were developed by third parties including private individuals. Further analysis was made, and important recommendations are suggested in this paper for a better utilization of e-government smartphone applications. These recommendations will result in better discoverability, maturity, and usefulness of e-government applications.

Keywords: mobile applications, e-government, m-government, Google Play Store

Procedia PDF Downloads 144
8787 Tourist Attraction through Agricultural Way of Life: A Case Study at Tra Que Village, Quang Nam Province, Vietnam

Authors: Ha Van Trung, Suchint Simaraks

Abstract:

Agro-tourism is a form of rural tourism that has actively developed in recent years. Tra Que vegetable village has developed this type of tourism to meet the needs of visitors to visit and experience. However, in the process of agricultural tourism development, Tra Que village is facing many issues related to the agricultural way of life, affecting the attraction of tourists. The purpose of this study is to find those issues. The survey questionnaire of 71 households and a semi-structured group interview of 30 households has been applied for the data collection. Research results show that there is a shortage of young workers, lack of training in tourism and agricultural production, and households only exploit a few agricultural activities for tourism. The number of households receiving tourists tends to decrease, and the number of households selling products to tourists at farms accounts for a small proportion. These will affect sustainable agro-tourism development in the future. Focusing on training local households in tourism and agricultural production, encourage young generation to preserve the agricultural way of life, upgrade infrastructure and public services, develop agro-products and tourism services will contribute to the sustainable development of agro-tourism in Tra Que vegetable village in the future.

Keywords: agro-tourism, way of life, Vietnamese tourists, Tra Que vegetable village

Procedia PDF Downloads 122
8786 Impact of COVID-19 Pandemic in the European Air Transport Command during 2020-2021

Authors: Martin Gascón Hove, Ralph Vermeltfoort, Alessandro Fiorini, Erwan Dulaurent, Henning von Perbandt

Abstract:

Introduction: The outbreak of the COVID-19 pandemic has completely changed the global health situation, with more than 400 million cases published and over 5 million deaths. European Air Transport Command (EATC) is integrated by seven nations, and among its capabilities is that of aeromedical evacuation (AM). Material and methods: Impact of novel coronavirus was analysed based on the number and characteristics of patients and executed missions within EATC and, particularly by Spain, during the biennium 2020-2021. Results: One thousand sixty patients were transported in 186 missions. Neither death nor disease contagion was reported during AM performances. Military cases transferred were 986, mostly routine priority (91,4%), and 74 were civilians, who were transported in 17 missions, and 81,1% of which were categorized as urgent. Niger led the list of original countries, with 191 evacuated patients. 76,1% of requests came from Italy and Germany. Airbus A310 was the most used aircraft (32,2%). Germany transported 222 patients of another nationality, while Spain executed eight missions and repatriated 68 cases, 58 of which were from Mali. Conclusions: COVID-19 has led to a surged number of evacuated patients inside EATC, which has proven to be a safe and effective means of transportation, even in critical cases. Spain has gained prominence since its annexation in 2015.

Keywords: COVID-19, SARS-CoV-2, pandemic, aviation, Spain

Procedia PDF Downloads 138
8785 STML: Service Type-Checking Markup Language for Services of Web Components

Authors: Saqib Rasool, Adnan N. Mian

Abstract:

Web components are introduced as the latest standard of HTML5 for writing modular web interfaces for ensuring maintainability through the isolated scope of web components. Reusability can also be achieved by sharing plug-and-play web components that can be used as off-the-shelf components by other developers. A web component encapsulates all the required HTML, CSS and JavaScript code as a standalone package which must be imported for integrating a web component within an existing web interface. It is then followed by the integration of web component with the web services for dynamically populating its content. Since web components are reusable as off-the-shelf components, these must be equipped with some mechanism for ensuring their proper integration with web services. The consistency of a service behavior can be verified through type-checking. This is one of the popular solutions for improving the quality of code in many programming languages. However, HTML does not provide type checking as it is a markup language and not a programming language. The contribution of this work is to introduce a new extension of HTML called Service Type-checking Markup Language (STML) for adding support of type checking in HTML for JSON based REST services. STML can be used for defining the expected data types of response from JSON based REST services which will be used for populating the content within HTML elements of a web component. Although JSON has five data types viz. string, number, boolean, object and array but STML is made to supports only string, number and object. This is because of the fact that both object and array are considered as string, when populated in HTML elements. In order to define the data type of any HTML element, developer just needs to add the custom STML attributes of st-string, st-number and st-boolean for string, number and boolean respectively. These all annotations of STML are used by the developer who is writing a web component and it enables the other developers to use automated type-checking for ensuring the proper integration of their REST services with the same web component. Two utilities have been written for developers who are using STML based web components. One of these utilities is used for automated type-checking during the development phase. It uses the browser console for showing the error description if integrated web service is not returning the response with expected data type. The other utility is a Gulp based command line utility for removing the STML attributes before going in production. This ensures the delivery of STML free web pages in the production environment. Both of these utilities have been tested to perform type checking of REST services through STML based web components and results have confirmed the feasibility of evaluating service behavior only through HTML. Currently, STML is designed for automated type-checking of integrated REST services but it can be extended to introduce a complete service testing suite based on HTML only, and it will transform STML from Service Type-checking Markup Language to Service Testing Markup Language.

Keywords: REST, STML, type checking, web component

Procedia PDF Downloads 245
8784 A Process FMEA in Aero Fuel Pump Manufacturing and Conduct the Corrective Actions

Authors: Zohre Soleymani, Meisam Amirzadeh

Abstract:

Many products are safety critical, so proactive analysis techniques are vital for them because these techniques try to identify potential failures before the products are produced. Failure Mode and Effective Analysis (FMEA) is an effective tool in identifying probable problems of product or process and prioritizing them and planning for its elimination. The paper shows the implementation of FMEA process to identify and remove potential troubles of aero fuel pumps manufacturing process and improve the reliability of subsystems. So the different possible causes of failure and its effects along with the recommended actions are discussed. FMEA uses Risk Priority Number (RPN) to determine the risk level. RPN value is depending on Severity(S), Occurrence (O) and Detection (D) parameters, so these parameters need to be determined. After calculating the RPN for identified potential failure modes, the corrective actions are defined to reduce risk level according to assessment strategy and determined acceptable risk level. Then FMEA process is performed again and RPN revised is calculated. The represented results are applied in the format of a case study. These results show the improvement in manufacturing process and considerable reduction in aero fuel pump production risk level.

Keywords: FMEA, risk priority number, aero pump, corrective action

Procedia PDF Downloads 278
8783 Hollowfiber Poly Lactid Co-Glycolic Acid (PLGA)-Collagen Coated by Chitosan as a Candidate of Small Diameter Vascular Graft

Authors: Dita Mayasari, Zahrina Mardina, Riki Siswanto, Agresta Ifada, Ova Oktavina, Prihartini Widiyanti

Abstract:

Heart failure is a serious major health problem with high number of mortality per year. Bypass is one of the solutions that has often been taken. Natural vascular graft (xenograft) as the substitute in bypass is inconvenient due to ethic problems and the risk of infection transmission caused by the usage of another species transgenic vascular. Nowadays, synthetic materials have been fabricated from polymers. The aim of this research is to make a synthetic vascular graft with great physical strength, high biocompatibility, and good affordability. The method of this research was mixing PLGA and collagen by magnetic stirrer. This composite were shaped by spinneret with water as coagulant. Then it was coated by chitosan with 3 variations of weight (1 gram, 2 grams, and 3 grams) to increase hemo and cytocompatibility, proliferation, and cell attachment in order for the vascular graft candidates to be more biocompatible. Mechanical strength for each variation was 5,306 MPa (chitosan 1 gram), 3,433 MPa (chitosan 2 grams) and 3,745 MPa (chitosan 3 grams). All the tensile values were higher than human vascular tensile strength. Toxicity test showed that the living cells in all variations were more than 60% in number, thus the vascular graft is not toxic.

Keywords: chitosan, collagen, PLGA, spinneret

Procedia PDF Downloads 392
8782 Comparative Toxicity of Garlic Juice and Dicofol to Population of Citrus Mites

Authors: Y. Atibi, A. Boutaleb Joutei, T. Slimani

Abstract:

Insecticidal properties of Alliaceae are widely known, they are plant with varied biological properties. Garlic and onion are known for their positive effect on health, including the prevention of cardiovascular disease and some digestive cancers. These health benefits molecules are also responsible for pest potential control of Alliaceae. With these properties, we can consider using Alliaceae as acaricides. The purpose of this study was to compare the effect of chemical and biopesticides on citrus mites, especially Tetranychus urticae, Panonychus citri and Eutetranychus orientalis. Chemical treatment (Dicofol) and biopesticides (Garlic juice + Alcohol) applied on this study to control the various stages of mites, have reduced the proliferation of mobile forms and reducing the number of eggs to acceptable levels. Garlic juice + alcohol revealed efficiency from 50 to 57.69 % against the mobile forms of T. urticae, however, it was effective against the mobile forms of P. citri and E. orientalis with an efficiency of 85.71 % and 100 % respectively, its action has also reduced the number of eggs of T. urticae and E. orientalis at low levels. Therefore, this biopesticide is conceivable viewpoint technical and economic as the infestation by mite is low.

Keywords: Garlic juice, acaricide, biopesticide, mites, alcohol, Tetranychus urticae, Panonychus citri, Eutetranychus orientalis.

Procedia PDF Downloads 516
8781 Field Management Solutions Supporting Foreman Executive Tasks

Authors: Maroua Sbiti, Karim Beddiar, Djaoued Beladjine, Romuald Perrault

Abstract:

Productivity is decreasing in construction compared to the manufacturing industry. It seems that the sector is suffering from organizational problems and have low maturity regarding technological advances. High international competition due to the growing context of globalization, complex projects, and shorter deadlines increases these challenges. Field employees are more exposed to coordination problems than design officers. Execution collaboration is then a major issue that can threaten the cost, time, and quality completion of a project. Initially, this paper will try to identify field professional requirements as to address building management process weaknesses such as the unreliability of scheduling, the fickleness of monitoring and inspection processes, the inaccuracy of project’s indicators, inconsistency of building documents and the random logistic management. Subsequently, we will focus our attention on providing solutions to improve scheduling, inspection, and hours tracking processes using emerging lean tools and field mobility applications that bring new perspectives in terms of cooperation. They have shown a great ability to connect various field teams and make informations visual and accessible to planify accurately and eliminate at the source the potential defects. In addition to software as a service use, the adoption of the human resource module of the Enterprise Resource Planning system can allow a meticulous time accounting and thus make the faster decision making. The next step is to integrate external data sources received from or destined to design engineers, logisticians, and suppliers in a holistic system. Creating a monolithic system that consolidates planning, quality, procurement, and resources management modules should be our ultimate target to build the construction industry supply chain.

Keywords: lean, last planner system, field mobility applications, construction productivity

Procedia PDF Downloads 110
8780 Modelling and Simulation of Cascaded H-Bridge Multilevel Single Source Inverter Using PSIM

Authors: Gaddafi Sani Shehu, Tankut Yalcınoz, Abdullahi Bala Kunya

Abstract:

Multilevel inverters such as flying capacitor, diode-clamped, and cascaded H-bridge inverters are very popular particularly in medium and high power applications. This paper focuses on a cascaded H-bridge module using a single direct current (DC) source in order to generate an 11-level output voltage. The noble approach reduces the number of switches and gate drivers, in comparison with a conventional method. The anticipated topology produces more accurate result with an isolation transformer at high switching frequency. Different modulation techniques can be used for the multilevel inverter, but this work features modulation techniques known as selective harmonic elimination (SHE).This modulation approach reduces the number of carriers with reduction in Switching Losses, Total Harmonic Distortion (THD), and thereby increasing Power Quality (PQ). Based on the simulation result obtained, it appears SHE has the ability to eliminate selected harmonics by chopping off the fundamental output component. The performance evaluation of the proposed cascaded multilevel inverter is performed using PSIM simulation package and THD of 0.94% is obtained.

Keywords: cascaded H-bridge multilevel inverter, power quality, selective harmonic elimination

Procedia PDF Downloads 411
8779 Identification of Genes Regulating Differentiation and Stemness of Human Mesenchymal Stem Cells for Gene Therapy in Regenerative Medicine

Authors: Tong Ming Liu

Abstract:

Human mesenchymal stem cells (MSCs) represent the most used stem cells for clinical application, which have been used in over 1000 clinical trials to treat over 30 diseases due to multilineage differentiation potential, secretome and immunosuppression. Gene therapies of MSCs hold great promise in the treatment of many diseases due to enhanced MSC-based clinical outcomes. To identify genes for gene therapy of MSCs, by comparing gene expression profile before and after MSC differentiation following by functional screening, we have identified ZNF145 that regulated MSC differentiation. Forced expression of ZNF145 resulted in enhanced in vitro chondrogenesis of MSCs as an upstream factor of SOX9 and improved osteochondral repair upon implant into osteochondral defects in rodents. By comparing gene expression profile during differentiation of iPSCs toward MSCs, we also identified gene HOX regulating MSC stemness, which was much downregulated in late-passaged MSCs. Knockdown of this gene greatly compromised MSC stemness including abolished proliferation, decreased CFU-F, promoted senescence and reduced expression of cell surface antigens linked to the MSC phenotype. In addition, multi-linage differentiation was also greatly impaired. Notably, HOX overexpression resulted in improved multi-lineage differentiation. In the mechanism, HOX expression significantly deceased in late passage of MSCs compared with early passage of MSCs, correlating with MSC important genes. ChIP-seq data shown that HOX binds to genes related to MSC self-renewal and differentiation. Most importantly, most HOX binding sites are lost in late passage of MSCs. HOX exerts its effects by directing binding Twist1, one important gene of MSCs. The identification of the genes regulating MSC differentiation and stemness will provide and promising strategies for gene therapy of MSCs in regenerative medicine.

Keywords: mesenchymal stem cell, novel transcription factor, stemness, gene therapy, cartilage repair, signaling pathway

Procedia PDF Downloads 49
8778 Criteria for Good Governance in Georgian Defense Sector:Standards and Principles

Authors: Vephkhvia Grigalashvili

Abstract:

This paper provides an overview of criteria for good governance in Georgian defense sector and scientific outcomes of comparative research. A respect for good governance and its realization into Georgian national defense sector represents a fundamental institutional necessity as well as country`s politico-legal obligation within the framework of the existing collaboration mechanisms with NATO (especially Building Integrity (BI) Programme) and the Association Agreement between the EU and Georgia. Furthermore good governance is considered as a democracy measuring criterion in country`s Euro-Atlantic integration process. Accordingly, integration and further development of the contemporary approaches of good governance into Georgian defense management model represents a burning issue of the country. The assessment of an existing model of the country, identification of defects and determination of course of institutional reforms in a mutual comparison format of good governance mechanisms of NATO or/and the EU member Eastern European or Baltic countries positively assessed by the international organizations is considered as a precondition for its effective realization. Scientific aims of this study are: (a) to conduct comparative analysis of Georgian national principles and generalized standards of NATO or/and the EU member Eastern European and Baltic countries in following segments of good governance: open governance; anticorruption policy; conflict of interests; integrity; internal and external control bodies; (b) to formulate theoretical and practical recommendations on reforms to be implemented in the country`s national defence sector. As research reveals, although, institutional / legal pillars of good governance in Georgian defense sector generally are in compliance with international principles, the quality of implementation of good government norms still remains as an area that needs further development by raising awareness of public servants and community.

Keywords: anti-corruption policy within Georgian defense governance, conflict of interests within Georgian defense governance, good governance in Georgian defense sector, principles of integrity in Georgian defense management

Procedia PDF Downloads 159
8777 An Investigation of the Effects of Word Length on Amblyopic Eye Movement during Reading

Authors: Yahya Maeni

Abstract:

It is well established that amblyopic patients have a reduced reading performance and oculomotor deficits. Word length has a significant impact on reading performance and eye movement behaviour during reading. As there no previous attempts to assess whether amblyopic eyes would be affected by word length while reading. This study aims to assess the effect of word length on amblyopic eye movement behaviour during reading including fixation duration, number of fixation and gaze duration. 21 adults with amblyopia and 21 age-matched controls participated in the study (age ± SD) (23.80 ± 4.66) for amblyopes and (24.20 ± 3.58) for Controls. Eye movement was recorded during reading binocularly using Eyelink 1000. Study was designed as 2 x 2 (amblyopia vs. control) x 2 lengths (4 letters, and 8 letters). Compared to controls, the amblyopic participants report significant longer duration of fixation, higher number of fixation and longer gaze duration for short words with far higher significant difference for long words. It could be concluded that eye movement in amblyopia during reading might be accounted for by the length of a word within a text and this could possible explanation of reduced reading performance among amblyopes. By understanding the effect of word length on amblyopia will shed light on reading deficits in amblyopia and help to determine the reading needs of amplyopes in educational and clinical settings.

Keywords: amblyopia, eye movement, reading, fixation

Procedia PDF Downloads 142
8776 Modeling and Simulating Productivity Loss Due to Project Changes

Authors: Robert Pellerin, Michel Gamache, Remi Trudeau, Nathalie Perrier

Abstract:

The context of large engineering projects is particularly favorable to the appearance of engineering changes and contractual modifications. These elements are potential causes for claims. In this paper, we investigate one of the critical components of the claim management process: the calculation of the impacts of changes in terms of losses of productivity due to the need to accelerate some project activities. When project changes are initiated, delays can arise. Indeed, project activities are often executed in fast-tracking in an attempt to respect the completion date. But the acceleration of project execution and the resulting rework can entail important costs as well as induce productivity losses. In the past, numerous methods have been proposed to quantify the duration of delays, the gains achieved by project acceleration, and the loss of productivity. The calculation related to those changes can be divided into two categories: direct cost and indirect cost. The direct cost is easily quantifiable as opposed to indirect costs which are rarely taken into account during the calculation of the cost of an engineering change or contract modification despite several research projects have been made on this subject. However, proposed models have not been accepted by companies yet, nor they have been accepted in court. Those models require extensive data and are often seen as too specific to be used for all projects. These techniques are also ignoring the resource constraints and the interdependencies between the causes of delays and the delays themselves. To resolve this issue, this research proposes a simulation model that mimics how major engineering changes or contract modifications are handled in large construction projects. The model replicates the use of overtime in a reactive scheduling mode in order to simulate the loss of productivity present when a project change occurs. Multiple tests were conducted to compare the results of the proposed simulation model with statistical analysis conducted by other researchers. Different scenarios were also conducted in order to determine the impact the number of activities, the time of occurrence of the change, the availability of resources, and the type of project changes on productivity loss. Our results demonstrate that the number of activities in the project is a critical variable influencing the productivity of a project. When changes occur, the presence of a large number of activities leads to a much lower productivity loss than a small number of activities. The speed of reducing productivity for 30-job projects is about 25 percent faster than the reduction speed for 120-job projects. The moment of occurrence of a change also shows a significant impact on productivity. Indeed, the sooner the change occurs, the lower the productivity of the labor force. The availability of resources also impacts the productivity of a project when a change is implemented. There is a higher loss of productivity when the amount of resources is restricted.

Keywords: engineering changes, indirect costs overtime, productivity, scheduling, simulation

Procedia PDF Downloads 234