Search results for: utility value

Authors: Panupong Chanplin, Wilailuk Mepracha, Sathapath Kilaso

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The aims of this research were twofold: 1) to logo design of Huay Kon Border Market, Chaloemphrakiat District, Nan Province and 2) to study the level of tourist satisfaction towards logo design of Huay Kon Border Market, Chaloemphrakiat District, Nan Province. Tourist satisfaction was measured using four criteria: a unique product identity, ease of remembrance, product utility, and beauty/impressiveness. The researcher utilized a probability sampling method via simple random sampling. The sample consisted of 30 tourists in the Huay Kon Border Market. Statistics utilized for data analysis were percentage, mean, and standard deviation. The results suggest that tourist had high levels of satisfaction towards all four criteria of the logo design that was designed to target them. This study proposes that specifically logo designed of Huay Kon Border Market could also be implemented with other real media already available on the market.

Keywords: satisfaction, logo, design, Huay Kon border market

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Authors: Craig Mahlasi

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The Subtropical Thicket Biome has been in peril of transformation. Estimates indicate that as much as 63% of the Subtropical Thicket Biome is severely degraded. Agricultural expansion is the main driver of transformation. While several studies have sought to document and map the long term transformations, there is a lack of information on disturbance events that allow for timely intervention by authorities. Furthermore, tools that seek to perform continuous land cover change detection are often developed for forests and thus tend to perform poorly in thicket ecosystems. This study investigates the utility of Earth Observation data for continuous land cover change detection in Subtropical Thicket ecosystems. Temporal Neural Networks are implemented on a time series of Sentinel-2 observations. The model obtained 0.93 accuracy, a recall score of 0.93, and a precision score of 0.91 in detecting Thicket disturbances. The study demonstrates the potential of continuous land cover change in Subtropical Thicket ecosystems.

Keywords: remote sensing, land cover change detection, subtropical thickets, near-real time

Procedia PDF Downloads 132

Authors: Buse T. Aydın, Enver Ozdemir

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In this study, a double layer authentication scheme between the aircraft and the Air Traffic Control (ATC) tower is designed to prevent any unauthorized aircraft from introducing themselves as friends. The method is a combination of classical cryptographic methods and new generation physical layers. The first layer has employed the embedded key of the aircraft. The embedded key is assumed to installed during the construction of the utility. The other layer is a physical attribute (flight path, distance, etc.) between the aircraft and the ATC tower. We create a mathematical model so that two layers’ information is employed and an aircraft is authenticated as a friend or foe according to the accuracy of the results of the model. The results of the aircraft are compared with the results of the ATC tower and if the values found by the aircraft and ATC tower match within a certain error margin, we mark the aircraft as a friend. In this method, even if embedded key is captured by the enemy aircraft, without the information of the second layer, the enemy can easily be determined. Overall, in this work, we present a more reliable system by adding a physical layer in the authentication process.

Keywords: ADS-B, communication with physical layer security, cryptography, identification friend or foe

Procedia PDF Downloads 130

Authors: Li Ni, Pen ManMan, Li KenLi

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Clustering is an intensive research for some years because of its multifaceted applications, such as biology, information retrieval, medicine, business and so on. The expectation maximization (EM) is a kind of algorithm framework in clustering methods, one of the ten algorithms of machine learning. Traditionally, optimization of objective function has been the standard approach in EM. Hence, research has investigated the utility of evolutionary computing and related techniques in the regard. Chemical Reaction Optimization (CRO) is a recently established method. So the property embedded in CRO is used to solve optimization problems. This paper presents an algorithm framework (EM-CRO) with modified CRO operators based on EM cluster problems. The hybrid algorithm is mainly to solve the problem of initial value sensitivity of the objective function optimization clustering algorithm. Our experiments mainly take the EM classic algorithm:k-means and fuzzy k-means as an example, through the CRO algorithm to optimize its initial value, get K-means-CRO and FKM-CRO algorithm. The experimental results of them show that there is improved efficiency for solving objective function optimization clustering problems.

Keywords: chemical reaction optimization, expection maimization, initia, objective function clustering

Procedia PDF Downloads 684

Authors: Alberto Alcalá-Alvarez, Pablo Padilla-Longoria

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The present paper describes a framework for constructing mathematical networks encoding relevant musical information from a music score for structural analysis. These graphs englobe statistical information about music elements such as notes, chords, rhythms, intervals, etc., and the relations among them, and so become helpful in visualizing and understanding important stylistic features of a music fragment. In order to build such networks, musical data is parsed out of a digital symbolic music file. This data undergoes different analytical procedures from Graph Theory, such as measuring the centrality of nodes, community detection, and entropy calculation. The resulting networks reflect important structural characteristics of the fragment in question: predominant elements, connectivity between them, and complexity of the information contained in it. Music pieces in different styles are analyzed, and the results are contrasted with the traditional analysis outcome in order to show the consistency and potential utility of this method for music analysis.

Keywords: computational musicology, mathematical music modelling, music analysis, style classification

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Authors: Kuen-Ming Shu, Jyun-Wei Chen

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Encapsulated O-rings are specifically designed to address the problem of sealing the most hostile chemicals and extreme temperature applications. Ultrasonic vibration hot embossing and ultrasonic welding techniques provide a fast and reliable method to fabricate encapsulated O-ring. This paper performs the design and analysis method of the acoustic horns with double extrusion to process tube double side flange simultaneously. The paper deals with study through Finite Element Method (FEM) of ultrasonic stepped horn used to process a capsulated O-ring, the theoretical dimensions of horns, and their natural frequencies and amplitudes are obtained through the simulations of COMOSOL software. Furthermore, real horns were fabricated, tested and verified to proof the practical utility of these horns.

Keywords: encapsulated O-rings, ultrasonic vibration hot embossing, flange making, acoustic horn, finite element analysis

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Authors: Bernardo Cedano, Ahmed H. Eltom, Bob Hay, Jim Glass, Raga Ahmed

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The deployment of smart grid devices such as smart meters and smart switches (SS) supported by a reliable and fast communications system makes automated distribution possible, and thus, provides great benefits to electric power consumers and providers alike. However, more research is needed before the full utility of smart switch data is realized. This paper presents new automated switching techniques using SS within the electric power grid. A concise background of the SS is provided, and operational examples are shown. Organization and presentation of data obtained from SS are shown in the context of the future goal of total automation of the distribution network. The description of application techniques, the examples of success with SS, and the vision outlined in this paper serve to motivate future research pertinent to disturbance analysis automation.

Keywords: disturbance automation, electric power grid, smart grid, smart switches

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Authors: Ivana Kašparová, Emilie Pecharová

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The experience of radiological contamination of land, especially after the Chernobyl and Fukushima disasters have shown the need to explore possibilities to the capture of radionuclides in the area affected and to adapt the landscape management to this purpose ex –ante the considered accident in terms of prevention. The project‚ Minimizing the impact of radiation contamination on land in the emergency zone of Temelin NPP‘ (2012-2015), dealt with the possibility of utilization of wetlands as retention sites for water carrying radionuclides in the case of a radiation accident. A model artificial wetland was designed and adopted as a utility model by the Ministry of Industry and Trade of the Czech Republic. The article shows the conditions of construction of designed wetlands in the landscape with regard to minimizing the negative effect on agricultural production and enhancing the hydrological functionality of the landscape.

Keywords: artificial wetland, land use/ land cover, old maps, surface-to-water transport of radionuclides

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Authors: M. Mansouri, P. Jaklitsch, E. Teiniker

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SQL injection on web applications is a very popular kind of attack. There are mechanisms such as intrusion detection systems in order to detect this attack. These strategies often rely on techniques implemented at high layers of the application but do not consider the low level of system calls. The problem of only considering the high level perspective is that an attacker can circumvent the detection tools using certain techniques such as URL encoding. One technique currently used for detecting low-level attacks on privileged processes is the tracing of system calls. System calls act as a single gate to the Operating System (OS) kernel; they allow catching the critical data at an appropriate level of detail. Our basic assumption is that any type of application, be it a system service, utility program or Web application, “speaks” the language of system calls when having a conversation with the OS kernel. At this level we can see the actual attack while it is happening. We conduct an experiment in order to demonstrate the suitability of system call analysis for detecting SQL injection. We are able to detect the attack. Therefore we conclude that system calls are not only powerful in detecting low-level attacks but that they also enable us to detect high-level attacks such as SQL injection.

Keywords: Linux system calls, web attack detection, interception, SQL

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Authors: A. S. Mousa, R. I. Rajab, A. A. Pinto

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An envy behavioral game theoretical model with two types of homogeneous players is considered in this paper. The strategy space of each type of players is a discrete set with only two alternatives. The preferences of each type of players is given by a discrete utility function. All envy strategies that form Nash equilibria and the corresponding envy Nash domains for each type of players have been characterized. We use geometry to construct two dimensional envy tilings where the horizontal axis reflects the preference for players of type one, while the vertical axis reflects the preference for the players of type two. The influence of the envy behavior parameters on the Cartesian position of the equilibria has been studied, and in each envy tiling we determine the envy Nash equilibria. We observe that there are 1024 combinatorial classes of envy tilings generated from envy chromosomes: 256 of them are being structurally stable while 768 are with bifurcation. Finally, some conditions for the disparate envy Nash equilibria are stated.

Keywords: game theory, Nash equilibrium, envy Nash behavior, geometric tilings, bifurcation thresholds

Procedia PDF Downloads 187

Authors: Gebremeskel Hagos Gebremedhin, Feng Chong, Heyan Huang

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Software system is the combination of architecture and organized components to accomplish a specific function or set of functions. A good software architecture facilitates application system development, promotes achievement of functional requirements, and supports system reconfiguration. We describe three studies demonstrating the utility of our architecture in the subdomain of mobile office robots and identify software engineering principles embodied in the architecture. The main aim of this paper is to analyze prove architecture design and automatic re-architecting using machine learning. Intelligence software architecture and automatic re-architecting process is reorganizing in to more suitable one of the software organizational structure system using the user access dataset for creating relationship among the components of the system. The 3-step approach of data mining was used to analyze effective recovery, transformation and implantation with the use of clustering algorithm. Therefore, automatic re-architecting without changing the source code is possible to solve the software complexity problem and system software reuse.

Keywords: intelligence, software architecture, re-architecting, software reuse, High level design

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Authors: Ayodeji O. Falade, Leonard V. Mabinya, Uchechukwu U. Nwodo, Anthony I. Okoh

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Given the high utility of peroxidase in several industrial processes, the search for novel microorganisms with enhanced peroxidase production capacity is of keen interest. This study investigated the process conditions for optimum peroxidase production by Ensifer sp, new ligninolytic proteobacteria with peroxidase production potential. Also, some agricultural residues were valorized for peroxidase production under solid state fermentation. Peroxidase production was optimum at an initial medium pH 7, incubation temperature of 30 °C and agitation speed of 100 rpm using alkali lignin fermentation medium supplemented with guaiacol as the most effective inducer and ammonium sulphate as the best inorganic nitrogen. Optimum peroxidase production by Ensifer sp. was attained at 48 h with specific productivity of 12.76 ± 1.09 U mg⁻¹. Interestingly, probable laccase production was observed with optimum specific productivity of 12.76 ± 0.45 U mg⁻¹ at 72 h. The highest peroxidase yield was observed with sawdust as solid substrate under solid state fermentation. In conclusion, Ensifer sp. possesses the capacity for enhanced peroxidase production that can be exploited for various biotechnological applications.

Keywords: catalase-peroxidase, enzyme production, peroxidase, polymerase chain reaction, proteobacteria

Procedia PDF Downloads 271

Authors: Thomas L. McCullough, John D. Hague, Marylesa M. Howard, Matthew K. Kiser, Michael A. Mazur, Lance K. McLean, Johanna L. Turk

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Radiological search and mapping depends on the successful recognition of anomalies in large data sets which contain varied and dynamic backgrounds. We present a new algorithmic approach for real-time anomaly detection which is resistant to common detector imperfections, avoids the limitations of a source template library and provides immediate, and easily interpretable, user feedback. This algorithm is based on a continuous wavelet transform for variance reduction and evaluates the deviation between a foreground measurement and a local background expectation using methods from linear algebra. We also present a technique for recognizing and visualizing spectrally similar clusters of data. This technique uses Laplacian Eigenmap Manifold Learning to perform dimensional reduction which preserves the geometric "closeness" of the data while maintaining sensitivity to outlying data. We illustrate the utility of both techniques on real-world data sets.

Keywords: radiological search, radiological mapping, radioactivity, radiation protection

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Authors: Adolfo Cangas, Noelia Navarro

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The current study shows the assessment made by university students of a video game entitled Stigma-Stop where the characters present different mental disorders. The objective is that players have more real information about mental disorders and empathize with them and thus reduce stigma. The sample consisted of 169 university students studying degrees related to education, social care and welfare (i.e., Social Education, Psychology, Early Childhood Education, Special Education, and Social Work). The participants valued the video game positively, especially in relation to utility, being somewhat lower the score awarded to the degree of entertainment. They detect the disorders and point out that in many occasions they felt the same (particularly in the case of depression, being lower in agoraphobia and bipolar disorder, and even lower in the case of schizophrenia), most students recommend the use of the video game. They emphasize that Stigma-Stop offers intervention strategies, information regarding the symptomatology and sensitizes against stigma.

Keywords: schizophrenia, social stigma, students, mental health

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Authors: Edward W. Staley, Corban G. Rivera, Ashley J. Llorens

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Advances in reinforcement learning (RL) have resulted in recent breakthroughs in the application of artificial intelligence (AI) across many different domains. An emerging landscape of development environments is making powerful RL techniques more accessible for a growing community of researchers. However, most existing frameworks do not directly address the problem of learning in complex operating environments, such as dense urban settings or defense-related scenarios, that incorporate distributed, heterogeneous teams of agents. To help enable AI research for this important class of applications, we introduce the AI Arena: a scalable framework with flexible abstractions for distributed multi-agent reinforcement learning. The AI Arena extends the OpenAI Gym interface to allow greater flexibility in learning control policies across multiple agents with heterogeneous learning strategies and localized views of the environment. To illustrate the utility of our framework, we present experimental results that demonstrate performance gains due to a distributed multi-agent learning approach over commonly-used RL techniques in several different learning environments.

Keywords: reinforcement learning, multi-agent, deep learning, artificial intelligence

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Authors: Avi Harel

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Most accidents are commonly attributed in hindsight to human errors, yet most methodologies for safety focus on technical issues. According to the Black Swan theory, this paradox is due to insufficient data about the ways systems fail. The article presents a study of the sources of errors, and proposes a methodology for utility-oriented design, comprising methods for coping with each of the sources identified. Accident analysis indicates that errors typically result from difficulties of operating in exceptional conditions. Therefore, following STAMP, the focus should be on preventing exceptions. Exception analysis indicates that typically they involve an improper account of the operational scenario, due to deficiencies in the system integration. The methodology proposes a model, which is a formal definition of the system operation, as well as principles and guidelines for safety-oriented system integration. The article calls to develop and integrate tools for recording and analysis of the system activity during the operation, required to implement validate the model.

Keywords: accidents, complexity, errors, exceptions, interaction, modeling, resilience, risks

Procedia PDF Downloads 173

Authors: Usha Barahmand, Ali Khazaee, Goudarz Sadeghi Hashjin

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Coping motives are considered to be indicators of problematic substance use. The present investigation examined a model with emotional abuse as an antecedent and emotional dysregulation as a mediator leading to substance use. The intent of this study was to examine the associations between various types of childhood maltreatment and motives for substance use. The sample consisted of 72 male opiate users recruited from those enrolled for Methadone Maintenance treatment. Participants responded to measures of childhood maltreatment, emotion dysregulation, and motives for opiate use. All data were analyzed using Pearson's correlation coefficients and bootstrap analysis of mediation. Results supported the hypothesis that the experience of emotional abuse in childhood is associated with problems in regulating emotions which in turn correlates with opiate use as a way to cope with negative affect, to enhance positive effect or to obtain social rewards. Bootstrap analysis confirmed the mediating role of emotion dysregulation. Findings support the potential utility of further research into emotion dysregulation and motives as antecedents of problematic opiate use.

Keywords: childhood abuse, emotion dysregulation, motives, substance use

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Authors: Pedro Pablo Ramírez Sánchez, Alassane Ballé Ndiaye, Roberto Rendeiro Martín-Cejas

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The aim of this paper is to analyse the different environmental policies adopted in Europe for car emissions, to comment on some of the possible perverse effects generated and point out these policies which are considered more efficient under the environmental perspective. This paper is focused on passenger cars as this category is the most significant in road transport. The utility of this research lies in this being the first step or basis to improve and optimise actual policies. The methodology applied in this paper refers to a comparative analysis from a practical and theoretical point of view of European environmental policies in road transport. This work describes an overview of the road transport industry in Europe pointing out some relevant aspects such as the contribution of road transport to total emissions and the vehicle fleet in Europe. Additionally, we propose a brief practice guide with the combined policies in order to optimise their aim.

Keywords: air quality, climate change, emission, environment, perverse effect, road transport, tax policy

Procedia PDF Downloads 132

Authors: Tanveer Beg, Yasir H. Siddique, Gulshan Ara, Asfar S. Azmi, Mohammad Afzal

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Doxorubicin is a well-known DNA intercalating chemotherapy drug that is widely used for treatment of different cancers. Its clinical utility is limited due to the observed genotoxic side effects on healthy cells suggesting that newer combination and genoprotective regimens are urgently needed for the management of doxorubicin chemotherapy. Some dietary phytochemicals are well known for their protective mechanism of action and genistein from soy is recognized as an anti-oxidant with similar properties. Therefore, the present study investigates the effect of genistein against the genotoxic doses of doxorubicin by assessing chromosomal aberrations, sister chromatid exchanges, cell cycle kinetics, cell viability, apoptosis, and DNA damage markers in cultured human lymphocytes. Our results reveal that genistein treatment significantly suppresses genotoxic damage induced by doxorubicin. It is concluded that genistein has the potential to reduce the genotoxicity induced by anti-cancer drugs, thereby reducing the chances of developing secondary tumors during the therapy.

Keywords: apoptosis, DNA damage markers, doxorubicin, genistein, genotoxicity, human lymphocyte culture

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Authors: Surinder Deswal, Mahesh Pal

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The paper investigates the potential of support vector machines based regression approach to model the mass transfer capacity of multiple plunging jets, both vertical (θ = 90°) and inclined (θ = 60°). The data set used in this study consists of four input parameters with a total of eighty eight cases. For testing, tenfold cross validation was used. Correlation coefficient values of 0.971 and 0.981 (root mean square error values of 0.0025 and 0.0020) were achieved by using polynomial and radial basis kernel functions based support vector regression respectively. Results suggest an improved performance by radial basis function in comparison to polynomial kernel based support vector machines. The estimated overall mass transfer coefficient, by both the kernel functions, is in good agreement with actual experimental values (within a scatter of ±15 %); thereby suggesting the utility of support vector machines based regression approach.

Keywords: mass transfer, multiple plunging jets, support vector machines, ecological sciences

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Authors: Rajesh P.P., Md. Tabish Noori, Makarand M. Ghangrekar

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Methanogenic substrate loss is reported to be a major bottleneck in microbial fuel cell which significantly reduces the power production capacity and coulombic efficiency (CE) of microbial fuel cell (MFC). Nitroethane is found to be a potent inhibitor of hydrogenotrophic methanogens in rumen fermentation process. Influence of nitroethane pre-treated sewage sludge inoculum on suppressing the methanogenic activity and enhancing the electrogenesis in MFC was evaluated. MFC inoculated with nitroethane pre-treated anodic inoculum demonstrated a maximum operating voltage of 541 mV, with coulombic efficiency and sustainable volumetric power density of 39.85 % and 14.63 W/m3 respectively. Linear sweep voltammetry indicated a higher electron discharge on the anode surface due to enhancement of electrogenic activity while suppressing methanogenic activity. A 63 % reduction in specific methanogenic activity was observed in anaerobic sludge pre-treated with nitroethane; emphasizing significance of this pretreatment for suppressing methanogenesis and its utility for enhancing electricity generation in MFC.

Keywords: coulombic efficiency, methanogenesis inhibition, microbial fuel cell, nitroethane

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Authors: T. Ganesan, M. S. Aris, I. Elamvazuthi, Momen Kamal Tageldeen

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Terms set in power purchase agreements (PPA) challenge power utility companies in balancing between the returns (from maximizing power production) and securing long term supply contracts at capped production. The production limitation set in the PPA has driven efforts to maximize profits through efficient and economic power production. In this paper, a combined industrial-scale gas turbine (GT) - absorption chiller (AC) system is considered to cool the GT air intake for reducing the plant’s heat rate (HR). This GT-AC system is optimized while considering power output limitations imposed by the PPA. In addition, the proposed formulation accounts for uncertainties in the ambient temperature using Type-2 fuzzy programming. Using the enhanced chaotic differential evolution (CEDE), the Pareto frontier was constructed and the optimization results are analyzed in detail.

Keywords: absorption chillers (AC), turbine inlet air cooling (TIC), power purchase agreement (PPA), multiobjective optimization, type-2 fuzzy programming, chaotic differential evolution (CDDE)

Procedia PDF Downloads 277

Authors: Hanan Alsaeid Alshenawy

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Background: Cervical dysplasia, which is potentially precancerous, has increased in young women. Detection of cervical is important for reducing morbidity and mortality in cervical cancer. This study analyzes the immunohistochemical expression of p16, HPV L1 capsid protein and Ki67 in cervical intraepithelial lesions and correlates them with lesion grade to develop a set of markers for diagnosis and detect the prognosis of cervical cancer precursors. Methods: 75 specimens were analyzed including 15 cases CIN 1, 28 CIN 2, 20 CIN 3, and 12 cervical squamous carcinoma, besides 10 normal cervical tissues. They were stained for p16, HPV L1 and Ki-67. Sensitivity, specificity, predictive values and accuracy were evaluated for each marker. Results: p16 expression increased during the progression from CIN 1 to carcinoma. HPV L1 positivity was detected in CIN 2 and decreased gradually as the CIN grade increased but disappear in carcinoma. Strong Ki-67 expression was observed with high grades CIN and carcinoma. p16, HPV L1 and Ki67 were sensitive but with variable specificity in detecting CIN lesions. Conclusions: p16, HPV L1 and Ki67 are useful set of markers in establishing the risk of high-grade CIN. They complete each other to reach accurate diagnosis and prognosis.

Keywords: p16, HPV L1, Ki67, CIN, cervical carcinoma

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Authors: Tomasz Wejrzanowski, Łukasz Kaczmarek, Michał Maksimczuk

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High-resolution X-ray computed microtomography (µCT) is a non-destructive technique commonly used to determine the internal structure of reservoir rock sample. This study concerns µCT analysis of Silurian and Ordovician shales and mudstones from a borehole in the Baltic Basin, north of Poland. The spatial resolution of the µCT images obtained was 27 µm, which enabled the authors to create accurate 3-D visualizations and to calculate the ratio of pores and fractures volume to the total sample volume. A total of 1024 µCT slices were used to create a 3-D volume of sample structure geometry. These µCT slices were processed to obtain a clearly visible image and the volume ratio. A copper X-ray source filter was used to reduce image artifacts. Due to accurate technical settings of µCT it was possible to obtain high-resolution 3-D µCT images of low X-ray transparency samples. The presented results confirm the utility of µCT implementations in geoscience and show that µCT has still promising applications for reservoir exploration and characterization.

Keywords: fractures, material density, pores, structure

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Authors: Naya Masood, Russell Hodgson, Mark Tacey

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Purpose: Patients with acute diverticulitis (AD) have an increased risk of underlying colorectal cancer (CRC); however, those with uncomplicated AD may have the same underlying population risk. This study informs on an Australian AD population who were not routinely offered colonoscopic follow-up. Methods: A 2-year (July 2016 – June 2018) retrospective study of patients admitted with CT-confirmed acute diverticulitis was conducted. CT findings were categorised as ‘complicated’ and ‘uncomplicated’ and were correlated with the detection of cancer in subsequent colonoscopy or follow-up. Results: 67.7% (n=292) of 431 patients were seen to have had complicated AD on an abdominopelvic CT scan. Patients were complicated most commonly due to bowel wall thickening reported on CT (90.4%), perforation (20.2%), or an abscess (12%). Follow-up colonoscopic evaluation was conducted in 52.9% (n=228) of total cases of AD, out of which 156 suffered complicated AD and the rest uncomplicated. None of the uncomplicated AD patients in our cohort were found to have CRC. Of those with complicated AD, six were found to have CRC. Conclusion: The only CRC diagnoses were made in patients with complicated AD. Despite available evidence, a significant proportion of uncomplicated AD patients were still undergoing colonoscopy. There is scope to further safely decrease the number of colonoscopies performed in AD patients.

Keywords: acute diverticulitis, colonoscopy, colorectal cancer, advanced adenoma, complicated diverticulitis

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Authors: M. Rashid Hussain, Shady S. Refaat

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The high voltage power transformer is the most essential part of the electrical power utilities. Reliability on the transformers is the utmost concern, and any failure of the transformers can lead to catastrophic losses in electric power utility. The causes of transformer failure include insulation failure by partial discharge, core and tank failure, cooling unit failure, current transformer failure, etc. For the study of power transformer defects, finite element analysis (FEA) can provide valuable information on the severity of defects. FEA provides a more accurate representation of complex geometries because they consider thermal, electrical, and environmental influences on the insulation models to obtain basic characteristics of the insulation system during normal and partial discharge conditions. The purpose of this paper is the time domain analysis of defects 3D model of high voltage power transformer using FEA to study the electric field distribution at different points on the defects.

Keywords: power transformer, finite element analysis, dielectric response, partial discharge, insulation

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Authors: Li Ma, Meishuang Ma, Mengying Huang

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The quality of construction projects reflects the credit and responsibilities of construction contractors for the owners and the whole society. Because the construction contractors master more relevant information about the entrusted engineering project under construction while the owners are in unfavorable position of gaining information, asymmetric information may lead the contractors act against the owners in order to pursue their own interests. Building a powerful motivation mechanism is the key to guarantee investor economic interests and the life and property of users in construction projects. Based on principal-agent theory and game theory, the authors develop relevant mathematical models to analyze and compare the contractor’s utility functions under different combinations of contracts’ explicit incentive mechanism and reputation’s implicit incentive mechanism aiming at finding out the conditions for incentive validity. The research concludes that the most rational motivation way is to combine the explicit and implicit incentive effects of both contracts and reputation mechanism, and puts forth some measures for problems on account of China’s current situation.

Keywords: construction contractors, contract, reputation, incentive mechanism

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Authors: Foroozan Sadri, Mohammadmehdi Moulaii, Farkhondeh Vahdati

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Smart materials can create a great revolution in our built environment, as living systems do. In this research, the optimal structure of healthcare building envelopes is analyzed in terms of thickness according to the utility of the smart-nano materials as nontoxic substances in the region. The research method in this paper is based on library studies and simulation. Grasshopper program is employed to simulate thermal characteristics to achieve the optimum U-value in Semnan desert climate, according to Iranian national standards. The potential of healthcare envelope layouts in thermal properties development (primarily U-value) of these buildings is discussed due to the high thermal loads of healthcare buildings and also toxicity effects of conventional materials. As a result, envelope thicknesses are calculated, and the performance of the nano-PCM and gypsum wallboards are compared. A solution with comparable performance using smart-nano materials instead of conventional materials would determine a decrease in wall thickness.

Keywords: energy saving, exterior envelope, smart-nano materials, thermal performance, U-value

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Authors: Nur Aisyah Jalalludin, Arwindra Rizqiawan, Goro Fujita

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In this study, we aim to demonstrate a microgrid system experimental simulation for an easy understanding of a large-scale microgrid system. This model is required for industrial training and learning environments. However, in order to create an exact representation of a microgrid system, the laboratory-scale system must fulfill the requirements of a grid-connected inverter, in which power values are assigned to the system to cope with the intermittent output from renewable energy sources. Aside from that, during changes in load capacity, the grid-connected system must be able to supply power from the utility grid side and microgrid side in a balanced manner. Therefore, droop control is installed in the inverter’s control board to maintain equal power sharing in both sides. This power control in a stand-alone condition and droop control in a grid-connected condition must be implemented in order to maintain a stabilized system. Based on the experimental results, power control and droop control can both be applied in the system by comparing the experimental and reference values.

Keywords: droop control, droop characteristic, grid-connected inverter, microgrid, power control

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Authors: Abdulkadir Magaji

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This study analyzes and compares the actual measured and simulated performance of a 3.2 kwP grid-connected photovoltaic system. The system is located at the Outdoor Facility of Government Day secondary School Katsina State, which lies approximately between coordinate of 12°15′N 7°30′E. The system consists of 14 Mono crystalline silicon modules connected in two strings of 7 series-connected modules, each facing north at a fixed tilt of 340. The data presented in this study were measured in the year 2015, where the system supplied a total of 4628 kWh to the local electric utility grid. The performance of the system was simulated using PVsyst software using measured and Meteonorm derived climate data sets (solar radiation, ambient temperature and wind speed). The comparison between measured and simulated energy yield are discussed. Although, both simulation results were similar, better comparison between measured and predicted monthly energy yield is observed with simulation performed using measured weather data at the site. The measured performance ratio in the present study shows 58.4% is higher than those reported elsewhere as compared in the study.

Keywords: performance, evaluation, grid connection, photovoltaic system

Procedia PDF Downloads 162