• Title/Summary/Keyword: A level-set method

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A Conceptual Design of Spatial and Non-spatial Information for Water Hazard Information Management and Service (수재해 정보관리 및 서비스를 위한 공간, 비공간 정보 자료 개념 설계)

  • Lee, Jeong-Ju;Kim, Dong-Young;Jung, Young-Hun;Hwang, Eui-Ho;Chae, Hyo-Sok
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.2
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    • pp.21-29
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    • 2016
  • This study conducted a basic design of system and interface which provide both of spatial and non-spatial data for water hazard information management. This helps to decide directions of the future integrated water hazard information platform and possible technical examinations of the web-based system for the realization of the prototype. For user friendly system, this study did a survey to investigate the data format, service environment, image processing level and visualization type that users prefer. Also, authorization range was set up by type of the user group. In the water hazard information platform, the data and analysis algorithm were classified by the fields. Furthermore, the platform was consisted with six block systems according to the function and the interface and designed to flexibly mount or modify the additional functions. For a basic design of the data exchange method and protocols, a prototype was constructed by using the spatial information web service technology. The portal service system to visualize and provide spatial data was designed by the WMS/WFS type of OGC standard interface and the FTP/HTTP interface type through open source GIS software for server environment.

A Study of Active Labor Market Policy and Unemployment : An Analysis Using Fuller-Battese Model (적극적 노동시장정책의 실업 감소 효과에 관한 연구)

  • Kang, Chul-Hee;Kim, Kyo-Seong;Kim, Young-Bum
    • Korean Journal of Social Welfare
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    • v.45
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    • pp.7-39
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    • 2001
  • This paper examines the effect of active labor market policy on the unemployment rates in 8 welfare states. This paper focuses on the following questions: what are the major predictors of the changes in unemployment rates?; and what is the effect of active labor market policy in reducing unemployment rates? Using the data from Comparative Welfare States Data Set by Stephens (1997), Key Indicators of the Labour Market by ILO (1999) and Social Expenditure Database by OECD (1999), this paper attempts to answer the above research questions. Fuller-Battese model, a data analysis method in pooled cross-sectional time-series analysis, is adopted to identify variables predicting changes in unemployment rates. This paper analyzes the predictors by using 3 analysis models about 2 types of unemployment (overall unemployment and long term unemployment). Results are as follows: (1) economic variable such as changes in GDP has a positive effect in reducing unemployment rates; (2) active labor market policy has a positive effect in reducing unemployment rates as well; (3) job brokering service among 3 major active labor market programs has a positive effect in reducing unemployment rates; and (4) there is an interaction effect between unemployment benefit level and active labor market policy in reducing unemployment rates. Through the empirical analysis, this paper provides valuable knowledge about effects of active labor market policy on unemployment in 8 welfare states and discusses implications for the active labor market policy in Korea.

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Reynolds and froude number effect on the flow past an interface-piercing circular cylinder

  • Koo, Bonguk;Yang, Jianming;Yeon, Seong Mo;Stern, Frederick
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.3
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    • pp.529-561
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    • 2014
  • The two-phase turbulent flow past an interface-piercing circular cylinder is studied using a high-fidelity orthogonal curvilinear grid solver with a Lagrangian dynamic subgrid-scale model for large-eddy simulation and a coupled level set and volume of fluid method for air-water interface tracking. The simulations cover the sub-critical and critical and post critical regimes of the Reynolds and sub and super-critical Froude numbers in order to investigate the effect of both dimensionless parameters on the flow. Significant changes in flow features near the air-water interface were observed as the Reynolds number was increased from the sub-critical to the critical regime. The interface makes the separation point near the interface much delayed for all Reynolds numbers. The separation region at intermediate depths is remarkably reduced for the critical Reynolds number regime. The deep flow resembles the single-phase turbulent flow past a circular cylinder, but includes the effect of the free-surface and the limited span length for sub-critical Reynolds numbers. At different Froude numbers, the air-water interface exhibits significantly changed structures, including breaking bow waves with splashes and bubbles at high Froude numbers. Instantaneous and mean flow features such as interface structures, vortex shedding, Reynolds stresses, and vorticity transport are also analyzed. The results are compared with reference experimental data available in the literature. The deep flow is also compared with the single-phase turbulent flow past a circular cylinder in the similar ranges of Reynolds numbers. Discussion is provided concerning the limitations of the current simulations and available experimental data along with future research.

A Study on the Regeneration of SCR Catalyst Deactivated by Unburned Carbon Deposition (탄소침적으로 피독된 탈질 촉매의 재생에 관한 연구)

  • Moon, Seung-Hyun;Lee, Seung-Jae;Ryu, In-Soo
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.10
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    • pp.928-935
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    • 2010
  • A bag filter system was partially burnt down during a trial run of waste wood incineration boiler. This brought about unburned hydrocarbon which caused a rapid deactivation of low temperature SCR catalyst set up in two stage after the bag filter. The deactivated catalyst was investigated in order to trace the origin by several characterization methods such as XRD, EDX, BET, TGA, SEM. The deactivated catalyst was regenerated by different methods such as acid washing, water washing in ultrasonication, and calcination treatment under air condition. It is found the calcination treatment under air condition at $450^{\circ}C$ for 2 hours to be the best regeneration method. The catalytic activity was measured in the form of 2 cm ${\times}$ 2 cm ${\times}$ 10 cm (catalyst weight 10 g) honeycomb type. A deNOx efficiency of the regenerated catalyst showed 100% at $180^{\circ}C$ which is the same level of fresh one.

The Effect of Chest Extension Exercise and Bridge Exercise on FVC and FEV1 (가슴우리 확장운동과 교각운동이 노력성 폐활량과 1초간 노력성 날숨량에 미치는 영향)

  • Kim, Chung-Yoo;Bae, Won-Sik
    • Journal of The Korean Society of Integrative Medicine
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    • v.9 no.4
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    • pp.11-18
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    • 2021
  • Purpose : The purpose of this study was to investigate the effect on lung capacity of healthy men and women in their twenties by performing an intervention using the chest extension exercise and the bridge exercise, which are respiratory muscle strengthening exercises. Methods : Thirty adult men and women in their 20s participated in this study. All subjects participated in the study after hearing the explanation of the purpose and method of the study, filling out a consent form. All subjects were randomly assigned to the chest extension exercise (CEE) group and the bridge exercise (BE) group of fifteen each. Each exercise was performed twice a week for 4 weeks. Lung capacity was measured by forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) using spirometry. Lung capacity was measured before and after exercise. The measured data were compared through the dependent t-test and the independent t-test. The statistical significance level was set at .05. Results : After the intervention, the CEE group showed a significant increase in FVC and FEV1 compared to before the intervention (p<.05). After the intervention, the BE group also had a significant increase in FVC and FEV1 compared to before the intervention (p<.05). However, there was no difference in FVC and FEV1 between groups before and after the intervention (p>.05). Conclusion : There was no difference between groups in lung capacity after exercise. However, both the chest extension exercise and the bridge exercise increased FVC and FEV1, which was thought to be because both exercise methods were effective in increasing lung capacity. Therefore, both chest extension exercises and bridge exercises can be effectively applied as a way to increase lung capacity.

A Study on the Improvement of the Education System of Craft Design according to Convergence (융복합에 따른 공예디자인의 교육시스템 개선에 관한 연구)

  • Chun, Jung-Jin
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.4
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    • pp.291-297
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    • 2021
  • The current formal and memorized design repetition training and practice is wandering in the uniform flat design thinking expression. To change these two-dimensional current issues into a three-dimensional design method, set the direction for each grade level under the integrated convergence educational goal and carry out projects step by step to understand design, the principle of spatial composition, the introduction of traditional design history, and the overall design of craft design. Creative and practical skills such as approach should be cultivated. Designers can only be produced through systematic education and training. In order to lead society and succeed, a designer who has experienced solutions and countermeasures on how to adapt themselves to the demands of various changes in the times must come to the field. Education experts insisted on innovation of the organizational structure and subject of the education system, and emphasized the importance of education in response to the rapid pace of change in the 21st century. This study aims to propose an educational system that combines academic research with a structural approach to tasks by setting a project that reflects the needs of society for convergence practice in which design and adjacent disciplines are linked through understanding and analysis of these issues.

Analysis of Factors Affecting the Subjective Health Status of Middle-aged and Elderly in Korean (한국인 중·장년층의 주관적 건강상태에 영향을 미치는 요인 분석)

  • Jung-Hoon An;Chae-Mun Lee
    • Journal of Industrial Convergence
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    • v.21 no.1
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    • pp.193-200
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    • 2023
  • This study aims to investigated the status of perceived health status, subjective body recognition, and weight change according to age. In addition, the main factors of interest of middle-aged and elderly people were analyzed. This is a secondary data analysis study using data from the 7th Korea National Health and Nutrition Examination Survey(KNHANES VIII-3, 2016-2018), Korea Centers for Disease Control and Prevention. The data were analyzed the data using IBM SPSS 21.0 program. Frequency analysis and chi-square test method was conducted. The significance level was set at p <.01. As a result of the analysis, subjective body recognition and perceived health status were identified to have a statistically significant positive relationship (r=0.256, p<.01). Perceived health status and weight change measured for a year also showed a statistically significant positive relationship (r=0.303, p<.01). Therefore, it is anticipated that the findings of this study are used as basic data for seeking ways for better health, quality of life, and well-being, as the study examines subjective health status and various variables applicable to middle-aged people.

Memory Organization for a Fuzzy Controller.

  • Jee, K.D.S.;Poluzzi, R.;Russo, B.
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1993.06a
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    • pp.1041-1043
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    • 1993
  • Fuzzy logic based Control Theory has gained much interest in the industrial world, thanks to its ability to formalize and solve in a very natural way many problems that are very difficult to quantify at an analytical level. This paper shows a solution for treating membership function inside hardware circuits. The proposed hardware structure optimizes the memoried size by using particular form of the vectorial representation. The process of memorizing fuzzy sets, i.e. their membership function, has always been one of the more problematic issues for the hardware implementation, due to the quite large memory space that is needed. To simplify such an implementation, it is commonly [1,2,8,9,10,11] used to limit the membership functions either to those having triangular or trapezoidal shape, or pre-definite shape. These kinds of functions are able to cover a large spectrum of applications with a limited usage of memory, since they can be memorized by specifying very few parameters ( ight, base, critical points, etc.). This however results in a loss of computational power due to computation on the medium points. A solution to this problem is obtained by discretizing the universe of discourse U, i.e. by fixing a finite number of points and memorizing the value of the membership functions on such points [3,10,14,15]. Such a solution provides a satisfying computational speed, a very high precision of definitions and gives the users the opportunity to choose membership functions of any shape. However, a significant memory waste can as well be registered. It is indeed possible that for each of the given fuzzy sets many elements of the universe of discourse have a membership value equal to zero. It has also been noticed that almost in all cases common points among fuzzy sets, i.e. points with non null membership values are very few. More specifically, in many applications, for each element u of U, there exists at most three fuzzy sets for which the membership value is ot null [3,5,6,7,12,13]. Our proposal is based on such hypotheses. Moreover, we use a technique that even though it does not restrict the shapes of membership functions, it reduces strongly the computational time for the membership values and optimizes the function memorization. In figure 1 it is represented a term set whose characteristics are common for fuzzy controllers and to which we will refer in the following. The above term set has a universe of discourse with 128 elements (so to have a good resolution), 8 fuzzy sets that describe the term set, 32 levels of discretization for the membership values. Clearly, the number of bits necessary for the given specifications are 5 for 32 truth levels, 3 for 8 membership functions and 7 for 128 levels of resolution. The memory depth is given by the dimension of the universe of the discourse (128 in our case) and it will be represented by the memory rows. The length of a world of memory is defined by: Length = nem (dm(m)+dm(fm) Where: fm is the maximum number of non null values in every element of the universe of the discourse, dm(m) is the dimension of the values of the membership function m, dm(fm) is the dimension of the word to represent the index of the highest membership function. In our case then Length=24. The memory dimension is therefore 128*24 bits. If we had chosen to memorize all values of the membership functions we would have needed to memorize on each memory row the membership value of each element. Fuzzy sets word dimension is 8*5 bits. Therefore, the dimension of the memory would have been 128*40 bits. Coherently with our hypothesis, in fig. 1 each element of universe of the discourse has a non null membership value on at most three fuzzy sets. Focusing on the elements 32,64,96 of the universe of discourse, they will be memorized as follows: The computation of the rule weights is done by comparing those bits that represent the index of the membership function, with the word of the program memor . The output bus of the Program Memory (μCOD), is given as input a comparator (Combinatory Net). If the index is equal to the bus value then one of the non null weight derives from the rule and it is produced as output, otherwise the output is zero (fig. 2). It is clear, that the memory dimension of the antecedent is in this way reduced since only non null values are memorized. Moreover, the time performance of the system is equivalent to the performance of a system using vectorial memorization of all weights. The dimensioning of the word is influenced by some parameters of the input variable. The most important parameter is the maximum number membership functions (nfm) having a non null value in each element of the universe of discourse. From our study in the field of fuzzy system, we see that typically nfm 3 and there are at most 16 membership function. At any rate, such a value can be increased up to the physical dimensional limit of the antecedent memory. A less important role n the optimization process of the word dimension is played by the number of membership functions defined for each linguistic term. The table below shows the request word dimension as a function of such parameters and compares our proposed method with the method of vectorial memorization[10]. Summing up, the characteristics of our method are: Users are not restricted to membership functions with specific shapes. The number of the fuzzy sets and the resolution of the vertical axis have a very small influence in increasing memory space. Weight computations are done by combinatorial network and therefore the time performance of the system is equivalent to the one of the vectorial method. The number of non null membership values on any element of the universe of discourse is limited. Such a constraint is usually non very restrictive since many controllers obtain a good precision with only three non null weights. The method here briefly described has been adopted by our group in the design of an optimized version of the coprocessor described in [10].

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Degree of Enteral Tube Feeding in the Intensive Care Unit and Change in Nutritional Status (병원 중환자의 경관유동식 공급 현황 및 영양상태 변화)

  • Im, Hyeon-Suk;Park, Eun-Gyeong;Lee, Jong-Ho
    • Journal of the Korean Dietetic Association
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    • v.7 no.3
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    • pp.217-226
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    • 2001
  • It is important to supply adequate nutrition to critically ill patients, whose gastrointestinal system is properly functioning, through the enteral tube feeding if oral intake is impossible. In this study we investigated the changes in nutritional status with enteral tube feeding according to the volume required. We investigated the volume ordered according to the patient's requirements, volume infused according to the volume ordered in 41 enteral tube feeding patients in intensive care unit from Jannuary to July, 2000. Body weight, serum albumin level, and total lymphocyte count were evaluated to assess nutritional status. The mean fasting period was 5 days before the enteral feeding and patients whose fasting period over 3 days were 51%. The mean enteral tube feeding period was 29 days and method of feeding was nasogastric, bolus feeding 6 times per day. The volume ordered was 69.7% of the patients' recommended calorie and volume infused was 86.6% of their volume prescribed. Accordingly, the volume infused was estimated 61.7% of their volume required. Only 44.6% of their reqiured volume was infused within 3 days after enteral tube feeding was started. It took 16 days in average to meet the patients' recommended calorie; 56% of subjects still did not fully met their requirements by the end point. Among the impeding factors in supplying enteral tube feeding, factors related to the number of feeding were high residual volume in stomach, vomiting, gastrointestinal bleeding, abdominal distension and surgery. Factors related to the acctual infused volume were diarrhea, gastrointestinal bleeding, abdominal distension, airway management and tube reinsertion. Significant correlations were shown between the volume infused and changes in both the patients' weight and serum albumin level. Deviding the subjects into two groups by their infused volume, less than 70% and more than that, we compared the two to come up with a significant difference in their serum albumin level, -0.23 vs 0.21, and their body weight, -4.52 vs 0.12. In enteral tube feeding, the volume delivered in sufficient to the pateints' energy requirement can affect their nutriitional status in critically ill patient; adequate nutritional management plan is essential. It is necessary to make every effort to educate clinical staff and to set up a unified management program to prescribe adequate ammount of energy for the patient's nutritional requirement.

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Trends of Arsenic Maximum Levels on Agricultural Commodities and Processed Agricultural Products (농산물 및 농산가공품 중 비소 허용기준에 관한 국내외 동향)

  • Paik, Min-Kyoung;Kim, Won-Il;Yoo, Ji-Hyock;Kim, Jin-Kyoung;Kim, Mi-Jin;Im, Geon-Jae;Hong, Moo-Ki;Om, Ae-Son
    • Journal of Food Hygiene and Safety
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    • v.25 no.1
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    • pp.16-23
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    • 2010
  • Although concerns about Arsenic (As) contamination in agricultural foods have currently increased, there in on adequate international risk management standards for As particularly on agricultural commodities and processed agricultural products. This scenario holds true also in Korea. Australia, and New Zealand has determined the As maximum level (ML) but only on cereals grains which is based on total As contents. ln addition, Japan has regulated the ML based on trivalent As contents in agricultural commodities, which do not have legal restrictions. On the other hand, China has developed a systemic risk management to restrict the As contamination above MLs in agricultural commodities and processed agricultural products based on inorganic and total As contents. The establishment of an adequate analytical method for As specification in agricultural foods is essential to determine the acceptable level of As in agricultural food. Probabilistic approach may remove some uncertainties in calculating human risk assessment from As. It should be reviewed in terms of maximum levels to set the best scenario based on a realiability and availability to achieve effective As management on agricultural foods in Korea.