Search results for: chladni patterns control via frequency adjustment

Authors: Pasala Gopi, P. Linga Reddy

Abstract:

The response of the load frequency control problem in an multi-area interconnected electrical power system is much more complex with increasing size, changing structure and increasing load. This paper deals with Load Frequency Control of three area interconnected Power system incorporating Reheat, Non-reheat and Reheat turbines in all areas respectively. The response of the load frequency control problem in an multi-area interconnected power system is improved by designing PID controller using different tuning techniques and proved that the PID controller which was designed by Simulink Design Optimization (SDO) Software gives the superior performance than other controllers for step perturbations. Finally the robustness of controller was checked against system parameter variations

Keywords: load frequency control, pid controller tuning, step load perturbations, inter connected power system

Procedia PDF Downloads 647

Authors: S. J. Arif

Abstract:

In the presented technique, a simple method is given for accurate measurement and control of power frequency deviation. The sinusoidal signal for which the frequency deviation measurement is required is transformed to a low voltage level and passed through a zero crossing detector to convert it into a pulse train. Another stable square wave signal of 10 KHz is obtained using a crystal oscillator and decade dividing assemblies (DDA). These signals are combined digitally and then passed through decade counters to give a unique combination of pulses or levels, which are further encoded to make them equally suitable for both control applications and display units. The developed circuit using discrete components has a resolution of 0.5 Hz and completes measurement within 20 ms. The realized circuit is simulated and synthesized using Verilog HDL and subsequently implemented on FPGA. The results of measurement on FPGA are observed on a very high resolution logic analyzer. These results accurately match the simulation results as well as the results of same circuit implemented with discrete components. The proposed system is suitable for accurate measurement and control of power frequency deviation.

Keywords: digital encoder for frequency measurement, frequency deviation measurement, measurement and control systems, power systems

Procedia PDF Downloads 380

Authors: A. Luli, A. Santona

Abstract:

It is rare for individuals that are involved in a relationship to think about the possibility of having procreation problems in the near present or in the future. However, infertility is a condition that affects millions of people all around the world. Often, infertile individuals have to deal with experiences of psychological, relational and social problems. In these cases, they have to review their choices and take into consideration, if it is necessary, new ones. Different studies have examined the different decisions that infertile individuals have to go through dealing with infertility and its treatment, but none of them is focused on the decision-making style used by infertile individuals to solve their problem and on the factors that influences it. The aim of this paper is to define the style of decision-making used by infertile persons to give a solution to the ‘problem’ and the potential predictive role of the attachment and of the dyadic adjustment. The total sample is composed by 251 participants, divided in two groups: the experimental group composed by 114 participants, 62 males and 52 females, age between 25 and 59 years, and the control group composed by 137 participants, 65 males and 72 females, age between 22 and 49 years. The battery of instruments used is composed by: the General Decision Making Style (GDMS), the Experiences in Close Relationships Questionnaire Revised (ECR-R), Dyadic Adjustment Scale (DAS), and the Symptom Checklist-90-R (SCL-90-R). The results from the analysis of the samples showed a prevalence of the rational decision-making style for both males and females. No significant statistical difference was found between the experimental and control group. Also the analyses showed a significant statistical relationship between the decision making styles and the adult attachment styles for both males and females. In this case, only for males, there was a significant statistical difference between the experimental and the control group. Another significant statistical relationship was founded between the decision making styles and the adjustment scales for both males and females. Also in this case, the difference between the two groups was founded to be significant only of males. These results contribute to enrich the literature on the subject of decision-making styles in infertile individuals, showing also the predictive role of the attachment styles and the adjustment, confirming in this was the few results in the literature.

Keywords: adjustment, attachment, decision-making style, infertility

Procedia PDF Downloads 336

Authors: Muhammad Faizan Rehman Qureshi, Ahmed Al-Kaisy

Abstract:

Accurate estimation of traffic loads is critical for pavement and bridge design, among other transportation applications. Given the disproportional impact of heavier axle loads on pavement and bridge structures, truck and heavy vehicle traffic is expected to be a major determinant of traffic load estimation. Further, heavy vehicle traffic is also a major input in transportation planning and economic studies. The traditional method for estimating heavy vehicle traffic primarily relies on AADT estimation using Monthly Day of the Week (MDOW) adjustment factors as well as the percent heavy vehicles observed using statewide data collection programs. The MDOW factors are developed using daily and seasonal (or monthly) variation patterns for total traffic, consisting predominantly of passenger cars and other smaller vehicles. Therefore, while using these factors may yield reasonable estimates for total traffic (AADT), such estimates may involve a great deal of approximation when applied to heavy vehicle traffic. This research aims at assessing the approximation involved in estimating heavy vehicle traffic using MDOW adjustment factors for total traffic (conventional approach) along with three other methods of using MDOW adjustment factors for total trucks (class 5-13), combination-unit trucks (class 8-13), as well as adjustment factors for each vehicle class separately. Results clearly indicate that the conventional method was outperformed by the other three methods by a large margin. Further, using the most detailed and data intensive method (class-specific adjustment factors) does not necessarily yield a more accurate estimation of heavy vehicle traffic.

Keywords: traffic loads, heavy vehicles, truck traffic, adjustment factors, traffic data collection

Procedia PDF Downloads 29

Authors: Sibel Yoleri

Abstract:

In this research it is aimed to determine the adjustment of students who attend the first class at elementary school to school in terms of several variables. The study group of the research consists of 286 students (131 female, 155 male) who continue attending the first class of elementary school in 2013-2014 academic year, in the city center of Uşak. In the research, ‘Personal Information Form’ and ‘Walker-Mcconnell Scale of Social Competence and School Adjustment’ have been used as data collection tools. In the analysis of data, the t-test has been applied in the independent groups to determine whether the sampling group students’ scores of school adjustment differ according to the sex variable or not. For the evaluation of data identified as not showing normal distribution, Mann Whitney U test has been applied for paired comparison, Kruskal Wallis H test has been used for multiple comparisons. In the research, all the statistical processes have been evaluated bidirectional and the level of significance has been accepted as .05. According to the results gathered from the research, a meaningful difference could not been identified in the level of students’ adjustment to school in terms of sex variable. At the end of the research, it is identified that the adjustment level of the students who have started school at the age of seven is higher than the ones who have started school at the age of five and the adjustment level of the students who have preschool education before the elementary school is higher than the ones who have not taken.

Keywords: starting school, preschool education, school adjustment, Walker-Mcconnell Scale

Procedia PDF Downloads 492

Authors: Sultan Shujja, Farah Malik

Abstract:

The study examined the mediating role of peer rejection in direct relationship of parental rejection and psychological adjustment among adolescents. Researchers used self-report measures e.g., Parental Acceptance-Rejection Questionnaire (PARQ), Children Rejection Sensitivity Questionnaire (PARQ), and Personality Assessment Questionnaire (PAQ) to assess perception of parent-peer rejection, psychological adjustment among adolescents (14-18 years). Findings revealed that peer rejection did not mediate the parental rejection and psychological adjustment whereas parental rejection emerged as strong predictor when demographic variables were statistically controlled. On average, girls were psychologically less adjusted than that of boys. Despite of equal perception of peer rejection, girls more anxiously anticipated peer rejection than did the boys. It is suggested that peer influence on adolescents, specifically girls, should not be underestimated.

Keywords: peer relationships, parental perception, psychological adjustment, applied psychology

Procedia PDF Downloads 515

Authors: Nadereh Sohrabi Shegefti, Siamak Samani

Abstract:

Level of adjustment is the first index to check mental health. The aim of this study was developing a valid and reliable Multidimensional Adjustment Scale (MAS). The sample consisted of 150 college students. Multidimensional adjustment scale and Depression, Anxiety, and stress scale (DASS) were used in this study. Principle factor analysis, Pearson correlation coefficient, and Cornbach's Alpha were used to check the validity and reliability of the MAS. Principle component factor analysis showed a 5 factor solution for the MAS. Alpha coefficients for the MAS sub scales were ranged between .69 to .83. Test-retest reliability for MAS was .88 and the mean of sub scales- total score correlation was .88. All these indexes revealed an acceptable reliability and validity for the MAS. The MAS is a short assessment instrument with good acceptable psychometric properties to use in clinical filed.

Keywords: psychological adjustment, psychometric properties, validity, Pearson correlation

Procedia PDF Downloads 638

Authors: Ruoyu Mao

Abstract:

The fast-paced and high-stress lifestyle of modern cities is an important cause of mental health problems and chronic physical diseases, and at the same time, all kinds of health problems will react to physical and mental stress, further aggravating the health risks; therefore, stress adjustment should be considered as an important perspective of the spatial environment to intervene in the health of the population. The purpose of this paper is to analyse the structural and therapeutic characteristics of the built environment of urban parks, to analyse the path of its effect on the stress adjustment of the population, and to summarise the mechanism of the built environment of urban parks to intervene in the health of the population from the perspective of stress adjustment.

Keywords: stress adjustment, health interventions, urban parks, built environments

Procedia PDF Downloads 55

Authors: Panagiotis Platanitis

Abstract:

Purpose: This research paper seeks to review the empirical studies in the field of expatriate adjustment in East Asia in order to produce a thematic understanding of the current adjustment challenges, thus enabling practitioners to enrich their knowledge. Background: Learning to live, work, and function in a country and culture vastly different from that of one’s upbringing can pose some unique challenges in terms of adaptation and adjustment. This has led to a growing body of research about the adjustment of expatriate workers. Adjustment itself has been posited as a three-dimensional construct; work adjustment, interaction adjustment and general or cultural adjustment. Methodology: This qualitative systematic review has been conducted on all identified peer-reviewed empirical studies related to expatriate adjustment in East Asia. Five electronic databases (PsychInfo, Emerald, Scopus, EBSCO and JSTOR) were searched to December 2015. Out of 625 identified records, thorough evaluation for eligibility resulted in 15 relevant studies being subjected to data analysis. The quality of the identified research was assessed according to the Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields. The data were analysed by means of thematic synthesis for systematic reviews of qualitative research. Findings: Data analysis revealed five key themes. The themes developed were: (1) personality traits (2) types of adjustment, (3) language, (4) culture and (5) coping strategies. Types of adjustment included subthemes such as: Interaction, general, work, psychological, sociocultural and cross-cultural adjustment. Conclusion: The present review supported previous literature on the different themes of adjustment and it takes the focus from work and general adjustment to the psychological challenges and it introduces the psychological adjustment. It also gives a different perspective about the use of cross-cultural training and the coping strategies expatriates use when they are abroad. This review helps counselling psychologists to understand the importance of a multicultural approach when working with expatriates and also to be aware of what expatriates might face when working and living in East Asia.

Keywords: adjustment, counselling psychology, East Asia, expatriates

Procedia PDF Downloads 269

Authors: Fernando Duarte

Abstract:

The work aims to evaluate the use of classical image processing methodologies towards skin tone classification in dermatological images. The skin tone is an important attribute when considering several factor for skin cancer diagnosis. Currently, there is a lack of clear methodologies to classify the skin tone based only on the dermatological image. In this work, a recent released dataset with the label for skin tone was used as reference for the evaluation of classical methodologies for segmentation and adjustment of color space for classification of skin tone in dermatological images. It was noticed that even though the classical methodologies can work fine for segmentation and color adjustment, classifying the skin tone without proper control of the aquisition of the sample images ended being very unreliable.

Keywords: segmentation, classification, color space, skin tone, Fitzpatrick

Procedia PDF Downloads 41

Authors: Onur Onder, Celal Tanuca, Mahir Ozil, Halil Sen, Alkım Ozkan, Engin Ceylan, Ali Istek, Ozgur Saglam

Abstract:

White balance adjustment of LCD TVs is an important procedure which has a direct influence on quality perception. Existing methods adjust RGB gain and offset values in different white levels during production. This paper suggests an iterative method in which the gamma is pre-adjusted during the design stage, and only 80% white is adjusted during production by modifying only RGB gain values (offset values are not modified). This method reduces the white balance adjustment time, contributing to the total efficiency of the production. Experiment shows that the adjustment results are well within requirements.

Keywords: color temperature, LCD panel deviation, LCD TV manufacturing, white balance

Procedia PDF Downloads 223

Authors: M. F. Páramo, F. Cadaveira, M. S. Rodríguez

Abstract:

The first year at university is a critical period for personal-emotional and academic adjustment in emerging adults. Moreover, some studies show that alcohol consumption increases in young adults on transition to university. The main purpose of this study was to analyze the impact of hazardous alcohol consumption and gender on adjustment to university, understood as a multidimensional construct involving an array of demands. A sample of 300 first year students in Spain completed the Student Adaptation to College Questionnaire (SACQ) and the Alcohol Use Disorders Identification Test (AUDIT). Examination of the data by analysis of variance revealed that adjustment to university was lower in the students undertaking hazardous alcohol consumption than in the other students. Surprisingly, the personal-emotional adjustment of students with hazardous alcohol consumption was not lower than in the other students. Analysis of the gender effect revealed that levels of personal-emotional adjustment were higher in males than in females. This is our first study examining the influence of alcohol consumption on university adjustment. Future research should examine this relationship more closely, with the aim of designing public health strategies focused on limiting abusive consumption of alcohol in university students.

Keywords: alcohol consumption, first year university students, gender, SACQ

Procedia PDF Downloads 336

Authors: W. Du, X. Wang, Jun Cao, H. F. Wang

Abstract:

Due to the randomness and uncertainty of wind energy, modern power systems integrating large-scale wind generation will be significantly impacted in terms of system performance and technical challenges. System inertia with high wind penetration is decreasing when conventional thermal generators are gradually replaced by wind turbines, which do not naturally contribute to inertia response. The power imbalance caused by wind power or demand fluctuations leads to the instability of system frequency. Accordingly, the need to attach the supplementary virtual inertia control to wind farms (WFs) strongly arises. When multi-wind farms are connected to the grid simultaneously, the selection of which critical WFs to install the virtual inertia control is greatly important to enhance the stability of system frequency. By building the small signal model of wind power systems considering frequency regulation, the installation locations are identified by the geometric measures of the mode observability of WFs. In addition, this paper takes the impacts of grid topology and selection of feedback control signals into consideration. Finally, simulations are conducted on a multi-wind farms power system and the results demonstrate that the designed virtual inertia control method can effectively assist the frequency regulation.

Keywords: frequency regulation, virtual inertia control, installation locations, observability, wind farms

Procedia PDF Downloads 402

Authors: Ho-Jun Jo, Wook-Won Kim, Yong-Sung Kim, Jin-O Kim

Abstract:

The application of ESS (Energy Storage Systems) in the future grids has been the solution of the microgrid. However, high investment costs necessitate accurate modeling and control strategy of ESS to justify its economic viability and further underutilization. Therefore, the reasonable control strategy for ESS which is subjected to generator and usage helps to curtail the cost of investment and operation costs. The rated frequency in power system is decreased when the load is increasing unexpectedly; hence the thermal power is operated at the capacity of only its 95% for the Governor Free (GF) to adjust the frequency as reserve (5%) in practice. The ESS can be utilized with governor at the same time for the frequency response due to characteristic of its fast response speed and moreover, the cost of ESS is declined rapidly to the reasonable price. This paper presents the ESS control strategy to extend usage of the ESS taken account into governor’s ramp rate and reduce the governor’s intervention as well. All results in this paper are simulated by MATLAB.

Keywords: micro grid, energy storage systems, ramp rate, control strategy

Procedia PDF Downloads 394

Authors: Tariqul Islam, Shaheen Mollah

Abstract:

The study's main objective is to assess the relationship between psychological adjustment and parental acceptance-rejection, teacher acceptance-rejection, and best friend acceptance-rejection among secondary school students. This study was conducted on a sample of 300 (6th through 10th-grade students) recruited from over ten schools in Dhaka. While the schools were selected purposively, the respondents within each school were selected conveniently. The collected data were analyzed using Pearson product-moment correlation, hierarchical regression, and simultaneous regression analysis. The results showed that psychological adjustment is positively correlated with paternal, maternal, teacher, and best friend acceptance. The paternal acceptance was significantly connected with maternal acceptance. The teacher and best friend acceptance are correlated substantially with paternal and maternal acceptance. The hierarchical multiple regressions indicated that maternal, paternal, teacher, and best friend acceptance-rejection contributed significantly to students' psychological adjustment. The results revealed substantial independent contributions of maternal, paternal, teacher, and best friend acceptance on the students' psychological adjustment. The simultaneous regression analysis indicates that the maternal and best friend acceptances (but not paternal acceptance) were significant predictors of psychological adjustments. It showed that 41.7% variability in psychological adjustment could be explained by paternal, maternal, and best friend acceptance. The findings of the present study are exciting. They may contribute to developing insight in parents and best friends for behaving properly with their offspring and friend, respectively, for better psychological adjustment.

Keywords: adjustment, parenting, rejection, acceptance

Procedia PDF Downloads 149

Authors: Ajeevan Gautam, Gulam Anwer Khan, Pratibha Pokhrel

Abstract:

Introduction: Dermatoglyphics is the science which deals with the study of dermal ridge configuration on the digits, palms and soles. It is grooved by ridges and forms variety of configurations. The aim of the study was to identify dermal ridge patterns on fingertip of hypertensive patients and in normal population and to compare patterns among them. Methods: The subjects of the study were 130 hypertensives and 130 non-hypertensives cases of Kathmandu Valley aged between 40 to 80 years. Case history was recorded after consent finger prints were taken. Different parameters as whorl, loop, arch and composite patterns were studied and analysed. Result: It revealed, increased whorl pattern in hypertensive. It showed 65.69% whorl, 29.23% loop and 5.07% arch patterns in right hand of hypertensive people. In control, it was found to be 34.46% whorl, 58.15% loop and 5.38% arch patterns respectively. Similarly in left hand 63.69% whorl, 32% loop and 4.30% arch in hypertensive group. In control group it was 60.15% as loop, 35.69% as whorl and 15% as arch. Discussion: Based on findings of the result, it was concluded that the whorl, loop and arch patterns observed as 65.69%, 29.23% and 5.07% respectively in hypertensive cases in right hand. Similarly in left hand, it was found to be 4.30% as arch, 32% as loop and 63.69% as whorl patterns, but in normotensive subjects these patterns were recorded as 36.43%, 58.15%, 5.38% in right hand and 35.69%, 60.15%, 4.15% in left hand as whorl, loop and arch respectively.

Keywords: arch, dermatoglyphics, hypertension, loop, whorl

Procedia PDF Downloads 296

Authors: R. S. Sheu, H. Usman, M. S. Lawal

Abstract:

Takagi-Sugeno (T-S) fuzzy model based control of a load frequency deviation in a single machine with limit nonlinearity on power coefficient is presented in the paper. Two T-S fuzzy rules with only rotor angle variable as input in the premise part, and linear state space models in the consequent part involving characteristic matrices determined from limits set on the power coefficient constant are formulated, state feedback control gains for closed loop control was determined from the formulated Linear Matrix Inequality (LMI) with eigenvalue optimization scheme for asymptotic and exponential stability (speed of esponse). Numerical evaluation of the closed loop object was carried out in Matlab. Simulation results generated of both the open and closed loop system showed the effectiveness of the control scheme in maintaining load frequency stability.

Keywords: T-S fuzzy model, state feedback control, linear matrix inequality (LMI), frequency deviation control

Procedia PDF Downloads 399

Authors: Peter Unoh Bassey

Abstract:

The study examined the influence of Costa and McCrae’s Neo-PI Factor and early adolescent’s school social adjustment in Cross River State, Nigeria. The research adopted the causal-comparative design also known as the ex-post facto with about one thousand and eighteen (1,018) students who were randomly selected from one stream of JSS 1 classes in 19 schools out of seventy-three (73) in the study area. Data were collected using two instruments one is the NEO-PI scale, and students school social adjustment questionnaire. Three research questions and three research hypotheses were postulated and tested at 0.05 level of significance. The analysis of data was carried out using both the independent t-test statistics and the one-way analysis of variance (ANOVA). The analyzed result indicated that the five dimensions had a significant influence on students school social adjustment. A post hoc was equally carried out to show the relative significant difference among the study variables. In view of the above, it was recommended that teachers, parents and educational psychologists should be involved to enhance students the confidence to overcome their social adjustment problem.

Keywords: Costa and McCrae’s NEO-PI Factor, early adolescents, school, social adjustment

Procedia PDF Downloads 154

Authors: Fujio Takata

Abstract:

When governments levy taxes on labor income on the basis of a balanced budget rule, two steady states in an economy exist, of which one can cause two movement patterns, namely, indeterminacy paths and a saddle path. However, in this paper, we assume an economy with divisible labor, in which labor adjustment is made by an intensive margin. We demonstrate that there indeed exist the two paths in the economy and that there exists a critical condition dividing them. This is proved by establishing the relationship between a finite elasticity of labor with regard to real wages and the share of capital in output. Consequently, we deduce the existence of an upper limit in the share of capital in output for indeterminacy to occur. The largest possible value of that share is less than 0.5698.

Keywords: balanced budget rule, divisible labor, labor income taxation, two movement patterns

Procedia PDF Downloads 167

Authors: Fayssal Amrane, Azeddine Chaiba

Abstract:

In this paper, type-2 fuzzy logic control (T2FLC) and neuro-fuzzy control (NFC) for a doubly fed induction generator (DFIG) based on direct power control (DPC) with a fixed switching frequency is proposed for wind generation application. First, a mathematical model of the doubly-fed induction generator implemented in d-q reference frame is achieved. Then, a DPC algorithm approach for controlling active and reactive power of DFIG via fixed switching frequency is incorporated using PID. The performance of T2FLC and NFC, which is based on the DPC algorithm, are investigated and compared to those obtained from the PID controller. Finally, simulation results demonstrate that the NFC is more robust, superior dynamic performance for wind power generation system applications.

Keywords: doubly fed induction generator (DFIG), direct power control (DPC), neuro-fuzzy control (NFC), maximum power point tracking (MPPT), space vector modulation (SVM), type 2 fuzzy logic control (T2FLC)

Procedia PDF Downloads 423

Authors: Anisa Luli, Alessandra Santona

Abstract:

Wanting a child and experiencing the impossibility to conceive is a painful condition that often is linked to infertility and often leads infertile individuals to experience psychological, relational and social problems. In this situation, infertile couples have to review their choices and take into consideration new ones. Few studies have focused on the decision-making style used by infertile individuals to solve their problem and on the factors that influences it. The aim of this paper is to define the style of decision-making used by infertile persons to give a solution to the “problem” and the predictive role of the attachment, of the representations of the relationship with parents in childhood and of the dyadic adjustment. The total sample is composed by 251 participants, divided in two groups: the experimental group composed by 114 participants, 62 males and 52 females, age between 25 and 59 years, and the control group composed by 137 participants, 65 males and 72 females, age between 22 and 49 years. The battery of instruments comprises: General Decision Making Style (GDMS), Experiences in Close Relationships Questionnaire Revised (ECR-R), Dyadic Adjustment Scale (DAS), Parental Bonding Instrument (PBI) and Symptom Checklist-90-R (SCL-90-R). The results from the analysis of the samples showed a prevalence of the rational decision-making style for both males and females, experimental and control group. There have been founded significant statistical relationships between the attachment scales, the representations of the parenting style, the dyadic adjustment and the decision-making styles. These results contribute to enrich the literature on the subject of decision-making in infertile people and show the relationship between the attachment and decision-making styles, confirming the few results in literature.

Keywords: attachment, decision-making style, infertility, dyadic adjustment

Procedia PDF Downloads 584

Authors: Rihab Hamdi, Amel Hadri Hamida, Ouafae Bennis, Fatima Babaa, Sakina Zerouali

Abstract:

This paper features a sliding mode controller (SMC) for closed-loop voltage control of DC-DC three-cells buck converter connected in parallel, operating in continuous conduction mode (CCM), based on pulse-width modulation (PWM). To maintain the switching frequency, the approach is to incorporate a pulse-width modulation that utilizes an equivalent control, inferred by applying the SM control method, to produce a control sign to be contrasted and the fixed-frequency within the modulator. Detailed stability and transient performance analysis have been conducted using Lyapunov stability criteria to restrict the switching frequency variation facing wide variations in output load, input changes, and set-point changes. The results obtained confirm the effectiveness of the proposed control scheme in achieving an enhanced output transient performance while faithfully realizing its control objective in the event of abrupt and uncertain parameter variations. Simulations studies in MATLAB/Simulink environment are performed to confirm the idea.

Keywords: DC-DC converter, pulse width modulation, power electronics, sliding mode control

Procedia PDF Downloads 152

Authors: Khattab Al Qaisi, Nicholas Bowring

Abstract:

This paper presents the simulation results of the effects of sampling frequency on the total harmonic distortion (THD) of three-phase inverters using the space vector pulse width modulation (SVPWM) and space vector control (SVC) algorithms. The relationship between the variables was studied using curve fitting techniques, and it has been shown that, for 50 Hz inverters, there is an exponential relation between the sampling frequency and THD up to around 8500 Hz, beyond which the performance of the model becomes irregular, and there is an negative exponential relation between the sampling frequency and the marginal improvement to the THD. It has also been found that the performance of SVPWM is better than that of SVC with the same sampling frequency in most frequency range, including the range where the performance of the former is irregular.

Keywords: DSI, SVPWM, THD, DC-AC converter, sampling frequency, performance

Procedia PDF Downloads 489

Authors: Chen-Fang Tsai, Shin-Li Lu

Abstract:

Distribution-free control chart is an oncoming area from the statistical process control charts in recent years. Some researchers have developed various nonparametric control charts and investigated the detection capability of these charts. The major advantage of nonparametric control charts is that the underlying process is not specifically considered the assumption of normality or any parametric distribution. In this paper, two nonparametric exponentially weighted moving average (EWMA) control charts based on nonparametric tests, namely NE-S and NE-M control charts, are proposed for monitoring process variability. Generally, weighted moving average (GWMA) control charts are extended by utilizing design and adjustment parameters for monitoring the changes in the process variability, namely NG-S and NG-M control charts. Statistical performance is also investigated on NG-S and NG-M control charts with run rules. Moreover, sensitivity analysis is performed to show the effects of design parameters under the nonparametric NG-S and NG-M control charts.

Keywords: Distribution-free control chart, EWMA control charts, GWMA control charts

Procedia PDF Downloads 277

Authors: Michael Dolgin, Oz Hamtzani, Talma Kushnir

Abstract:

A literature review has shown that while parents of children with cancer experience increased levels of psychological distress associated with their child's medical condition, considerable variability in parental adjustment is evident. Of the factors that may account for this variability, little attention has been devoted to the simultaneous interaction of three coping constructs and their role in parental adjustment: (1) Coping techniques employed, (2) Repertoire of coping techniques, and (3) Flexibility in applying coping techniques. While these constructs have been studied individually in relation to adjustment in general, studies to date have not included them together within a single conceptual model and research design and evaluated them in a clinical population. The objective of the current study was to determine how these three coping technique constructs interact to impact parental adjustment to pediatric cancer. A cross-sectional sample of 145 parents of children in active cancer treatment completed standardized measures of coping techniques, repertoire, flexibility, and parental distress. A hierarchical multiple regression analysis demonstrated that 37% of the variance in parental distress was predicted by the use of avoidance-focused coping techniques [F(1,118)=69.843, p<.001], with an additional 3% predicted by coping repertoire [F(2,117)=7.63, p=.00] for a total of 40% variance explained. Coping flexibility was found to mediate the relationship between coping repertoire and parental distress. These findings suggest that coping techniques employed by parents (problem/emotion-focused vs. avoidance-focused), as well as coping repertoire, significantly impact parental adjustment. Flexibility in applying coping techniques within one’s coping repertoire further contributes to parental adjustment. Implications for further study and clinical intervention will be presented.

Keywords: coping techniques, repertoire, flexibility, adjustment

Procedia PDF Downloads 47

Authors: Yoshie Asahara, Hidekuni Takao

Abstract:

Non-invasive positive pressure ventilation (NPPV), a type of ventilation therapy, is a treatment in which a mask is attached to the patient's face and delivers gas into the mask to support breathing. The NPPV mask uses a strap, which is necessary to attach and secure the mask in the appropriate facial position, but the tensile strength of the strap is adjusted by the sensation of the hands. The strap uniformity and fine-tuning strap tension are judged by the skill of the operator and the amount felt by the finger. In the future, additional strap operation and adjustment methods will be required to meet the needs for reducing the burden on the patient’s face. In this study, we fabricated a mechanism that can measure, adjust and fix the tension of the straps. A small amount of strap tension can be adjusted by rotating the shaft. This makes it possible to control the slight strap tension that is difficult to grasp with the sense of the operator's hand. In addition, this mechanism allows the operator to control the strap while controlling the movement of the mask body. This leads to the establishment of a suitable mask fitting method for each patient. The developed mechanism enables the operation and fine reproducible adjustment of the strap tension and the mask balance, reducing the burden on the face.

Keywords: balance of the mask strap, fine adjustment, film sensor, mask fitting technique, mask strap tension

Procedia PDF Downloads 244

Authors: Deepak Choudhary

Abstract:

COEP-Microgrid, a project by the students of College of Engineering Pune aims at establishing a micro grid in the college campus serving as a living laboratory for research and development of novel grid technologies. Proposed micro grid has an AC-bus and DC-bus, interconnected together with a tie line DC-AC converter. In grid-connected mode AC bus of microgrid is synchronized with utility grid. Synchronization with utility grid requires grid and AC bus to have synchronism in frequency, phase sequence and voltage. Power flow requires phase difference between grid and AC bus. Control System is required to effectively regulate power flow between the grid and AC bus. The grid synchronizing control system is composed of frequency and phase control for regulated power flow and voltage control system for reduction of reactive power flow. The control system involves automatic active power flow control. It takes the feedback of DC link Capacitor and changes the power angle accordingly. Control system incorporating voltage, phase and power control was developed for grid-tie inverter. This paper discusses the design, simulation and practical implementation of control system described in various micro grid scenarios.

Keywords: microgrid, Grid-tie inverter, voltage control, automatic power control

Procedia PDF Downloads 669

Authors: Bincy Mathew, B. William Dharma Raja

Abstract:

Successful decision making in a social setting depends on the ability to understand the intentions, emotions and beliefs of others. Children live and grow in the social world. Individuals think to satisfy their curiosity and mush of their social thought is practical, to attain their goal. Children’s thought about their social world influences how they behave towards it. The main purpose of this paper is to review the influence of decision making on adjustment behaviour of visually challenged adolescents. The sample was purposively selected to study the cases of two of the visually challenged adolescents from a Special School, in Tirunelveli, Tamil Nadu, India. The authors appraised the observed behaviour of adjustment in these children. It may be concluded that the social cognitive ability of decision making is at least, to certain extent, influences adjustment behaviour of visually challenged adolescents. Adjustment behaviour attempts to maintain a child’s level of physiological and psychological equilibrium and it is directed towards tension reduction. It involves a state of harmonious relationship existing between the individual and one’s environment so that adjustment is a matter of interaction between the capacities of the individual and the demands of the environment. The study also found that music induces a receptive mood that generally enhances cognitive processing and every decision that the child makes has its brunt on the behaviour. It is solely based on the case study carried out by the authors.

Keywords: social cognition, decision making, adjustment behaviour, adolescents

Procedia PDF Downloads 260

Authors: Kamila Fethallah, Mahmoud Mekadem, Hamid Ouali

Abstract:

Active flow control around a cylinder is an extensively studied subject in aerodynamics. Researchers apply a range of techniques to alter the fluid flow surrounding a cylindrical body, with the intent of reducing drag, enhancing lift, and optimizing overall aerodynamic performance. This study investigates the manipulation of flow dynamics around a circular cylinder by introducing an original elliptical cylindrical deformation to the traditionally straight section. Through the use of a crank mechanism, precise control of the deformation is achieved, allowing a comprehensive examination of its effects on fluid flow patterns. The main objective of this research is to evaluate the effectiveness of this advanced approach in reducing the drag coefficient and modifying the wake pattern, providing valuable information on flow control and optimization. Experimental results show that varying deformation amplitudes (10%, 15% and 20%) and control frequencies strongly influence drag and flow structure, the maximum reduction in drag coefficient (approximately 44%) observed at 15% amplitude and optimum frequency. The flow structure is strongly influenced by the deformation amplitude and frequency, particularly in the frequency range close to that of the natural shedding. These results suggest that the deformation frequency and amplitude play a crucial role in modifying the flow structure and reducing the drag coefficient. Numerical simulations further support the efficiency of the active flow control technique using cylindrical-elliptical deformation, underlining a consistent drag reduction of up to 42% at extreme deformation conditions (100%). The present study aims at highlighting the potential of this original approach in the enhancement of efficiency and performance of systems involved in energy exchange with fluids. Concluding this, the current study offers fresh routes toward the development of flow control and optimization strategies in a wide range of engineering applications.

Keywords: control frequencies, deformation amplitudes, drag coefficient, elliptical cylindrical deformation, flow dynamics, wake pattern

Procedia PDF Downloads 12

Authors: Alhaji M. H. Conteh, Xiangbin Yan, Alfred V. Gborie

Abstract:

The goal of this study was to increase the awareness of the description and assessments of rice acreage response and to offer mechanisms for agricultural policy scrutiny. The Ordinary Least Square (OLS) technique was utilized to determine the coefficients of acreage response models for the rice varieties. The magnitudes of the coefficients (λ) of both the ROK lagged and NERICA lagged acreages were found positive and highly significant, which indicates that farmers’ adjustment rate was very low. Regarding lagged actual price for both the ROK and NERICE rice varieties, the short-run price elasticities were lower than long-run, which is suggesting a long-term adjustment of the acreage, is under the crop. However, the apparent recommendations for policy transformation are to open farm gate prices and to decrease government’s involvement in agricultural sector especially in the acquisition of agricultural inputs. Impending research have to be centred on how this might be better realized. Necessary conditions should be made available to the private sector by means of minimizing price volatility. In accordance with structural reforms, it is necessary to convey output prices to farmers with minimum distortion. There is a need to eradicate price subsidies and control, which generate distortion in the market in addition to huge financial costs.

Keywords: acreage response, rate of adjustment, rice varieties, Sierra Leone

Procedia PDF Downloads 327