• Journal of Intelligence and Information Systems
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• v.6 no.2
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• pp.29-40
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• 2000

Process planning (selection and ordering of processes) and material selection for product manufacturing are two key things determined before taking full-scale manufacturing. Knowledge on product design. material characteristics, processes, time and cost all-together are mutually related and should be considered concurrently. Due to the complexity of problem, human experts have got only one of the feasilbe solutions with their field knowledge and experiences. We propose a hierarchical expert system framework of knowledge representation and reasoning in order to overcome the complexity. Manufacturing processes have inherently hierarchical relationships, from top level processes to bottom level operation processes. Process plan of one level is posted in process blackboard and used for lower level process planning. Process information on blackboard is also used to adjust the process plan in order to resolve the dead-end or inconsistency situation during reasoning. Decision variables for process, material, tool, time and cost are represented as object frames, and their relationships are represented as constraints and rules. Constraints are for relationship among variables such as compatibility, numerical inequality etc. Rules are for causal relationships among variables to reflect human expert\`s knowledge such as process precedence. CRSP(Constraint and Rule Satisfaction Problem) approach is adopted in order to obtain solution to satisfy both constraints and rules. The trade-off procedure gives user chances to see the impact of change of important variables such as material, cost, time and helps to determine the preferred solution. We developed the prototype system using visual C++ MFC, UNIK, and UNlK-CRSP on PC.

• Membrane and Water Treatment
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• v.9 no.3
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• pp.155-162
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• 2018

Process modeling with activated sludge models (ASMs) is useful for the design and operational improvement of biological nutrient removal (BNR) processes. Effective utilization of ASMs requires the influent fraction analysis (IFA) of the wastewater treatment plant (WWTP). However, this is difficult due to the time and cost involved in the design and operation steps, thereby declining the simulation reliability. Harmony Search (HS) algorithm was utilized herein to determine the relationships between composite variables and state variables of the model IWA ASM1. Influent fraction analysis was used in estimating fractions of the state variables of the WWTP influent and its application to 9 wastewater treatment processes in South Korea. The results of influent $S_s$ and $Xs+X_{BH}$, which are the most sensitive variables for design of activated sludge process, are estimated within the error ranges of 8.9-14.2% and 3.8-6.4%, respectively. Utilizing the chemical oxygen demand (COD) fraction analysis for influent wastewater, it was possible to predict the concentrations of treated organic matter and nitrogen in 9 full scale BNR processes with high accuracy. In addition, the results of daily influent fraction analysis (D-IFA) method were superior to those of the constant influent fraction analysis (C-IFA) method.

• Korean Journal of Community Nutrition
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• v.23 no.6
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• pp.506-515
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• 2018

Objectives: We investigated the operation needs of school meal support centers (SMSC) in Chungnam-do based on analysis of nutrition teachers' perception of them. Methods: The Chungnam government established the first SMSC in 2012. Thirteen SMSCs are currently being operated in Chungnam-do. To analyze the results quantitatively, we investigated nutrition teachers opinions regarding the necessity for SMSCs as a dependent variable and derived the independent variables based on the causal relationships with dependent variables using the ordered logit model. Those independent variables included region, school type, number of students, attitude regarding free meal policy, satisfaction with school meal policy, and preference for local food. Results: Briefly, teachers in the region in which the SMSC was located more strongly supported the SMSC. In addition, teachers in public schools with a smaller number of students believed that having a SMSC is more beneficial, and that other variables also affected the necessity for SMSCs. Moreover, nutrition teachers preferred local foods rather than organic foods because of the unstable supply of organic foods. Conclusions: Based on the results of this study, it was recommended that the local government implement the policy consistently. Moreover, it was recommended that the government operate the SMSC more efficiently, enhance the roles of the SMSC as the local organization responsible for student nutritional planing and expand the coverage of agricultural products.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.7
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• pp.1-7
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• 2019

A chatter lobe analysis is frequently used to look at the chatter state. Even if there is a lot of research on chatter, chatter lobe characteristics are not well defined. In this study, the chatter lobe behavior according to several variables of vibration mode is verified for further clarity. The dynamic variables of the chatter model are defined and their behaviors on chatter lobe boundary are analyzed in detail. In this sense, the chatter model with 2-DOF (2-DOF) was used to analyze chatter stability characteristics. The discussed results are satisfying and these can be used for the prediction of chatter existence in machining processes of 2-DOF systems in several revolution range. These analyses indicate a better agreement for predicting an appropriate stability lobe over a wide detailed range of critical depths of cut in machining operation. The results allow an excellent prediction of chatter according to various static and dynamic variables in machining states. The behavior of chatter dynamic variables in machining were also discussed in detail. All these results can also be applied to other machining processes by establishing a chatter model in a 2-DOF system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1063-1070
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• 2008

The performance of an acoustic transducer is determined by the effects of many design variables, and mostly the influences of these design variables are not linearly independent of each other. To achieve the optimal performance of an acoustic transducer, we must consider the cross-coupled effects of the design variables. In this study, the variation of the performances of underwater acoustic transducer in relation to its structural variables was analyzed. In addition, the new optimal design scheme of an acoustic transducer that could reflect not only individual but also all the cross-coupled effects of multiple structural variables, and could determine the detailed geometry of the transducer with great efficiency and rapidity was developed. The validation of the new optimal design scheme was verified by applying the optimal structure design of a flextensional transducer which are the most common use for high power underwater acoustic transducer. With the finite element analysis(FEA), we analyzed the variation of the resonance frequency, sound pressure, and working depth of a flextensional transducer in relation to its design variables. Through statistical multiple regression analysis of the results, we derived functional forms of the resonance frequency, sound pressure, and working depth in terms of the design variables. By applying the constrained optimization technique, Sequential Quadratic Programming Method of Phenichny and Danilin(SQP-PD), to the derived function, we designed and verified the optimal structure of the Class IV flextensional transducer that could provide the highest sound pressure level and highest working depth at a given operation frequency of 1 kHz.

• Journal of Family Resource Management and Policy Review
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• v.14 no.4
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• pp.39-56
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• 2010

The purpose of this research was to analyze the relationship between environment-friendly housing behaviors and the influential variables among consumers by focusing on housing life. This research carried out a questionnaire survey with housewives living in Seoul and the Metropolitan area using a questionnaire that was composed based on previous research. The housewives' environment-friendly housing attitudes and their resource-saving knowledge level, along with environmental education-related variables, house ownership, and the housewives' employment appeared to be significant variables in explaining the generic environment-friendly housing behaviors found in this research. Three regression equations, classified into purchasing, utilization, and disposal behaviors, were employed. The empirical results were relatively similar to those for the generic environment-friendly housing behaviors; however, each model provided somewhat different results in some specific aspects. All the environmental education-related variables appeared to be significant in explaining environment-friendly housing utilization behaviors, and were similar to the results obtained from the generic environment-friendly housing behaviors. However, the variables were limited in explaining environment-friendly housing-related disposal behaviors. The convenience, recycling ease, and family-structure variables appeared to be significant influences on environment-friendly housing-related disposal behaviors. Most empirical results of this research were consistent with those of previous studies. However, the explanatory independent variables varied, depending on the types of each domain of environment-friendly housing behaviors studied.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.64-77
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• 2022

Objectives: The purpose of this study is to objectify the level of case management performance and the factors influencing performance, to improve the case management performance at the Korea Worker's Compensation & Welfare Service (KWCWS) on the basis of the recognition of the objective realities of case management by job coordinators at the KWCWS, to develop a model of case management fit for the KWCWS, and to provide a basis for establishing guidelines for standardized case management. Methods: A total of 156 questionnaires were distributed to job coordinators at the KWCWS's headquarters, six regional headquarters, and 55 branches. One hundred forty-one questionnaires were collected and 126 were analyzed statistically using SPSS 21.0. Factor analysis and reliability analysis were conducted to verify the validity and reliability of the main measurement items in the research model. Frequency analysis was conducted for general characteristics of survey subjects. Frequency analysis or descriptive statistics were conducted to identify the level of independent variables (case manager's individual variables, job variables, institutional and organizational variables). Dependent variables (case management performance) and the degree of correlation were analyzed through correlation analysis between research variables. Multiple regression analysis and hierarchical regression analysis were conducted to examine the effect of independent variables on case management performance. Results: The results of the study showed that the level of overall performance in the five stages of case management was ordinary, with an average level of 3.45 on a 5-point scale. Levels of performance by step were institutional approach and intake (3.69), assessment (3.63), goal setting and intervention planning (3.46), implementation of intervention plan (3.32), and evaluation and termination (3.20), in that order. The explanatory power of case management performance (overall) by case managers with the KWCWS was case manager's institutional and organizational variables, job variables, and individual variables, in that order. At each stage of case management, the explanatory power of a case manager's institutional and organizational variables was found to be the greatest. The model changes at each stage of case management assume similar aspects statistically. In hierarchical regression analysis, it was institutional support that had a significant effect on case management performance (overall), and institutional support had the greatest effect. The results of multiple regression analysis in which all variables are input simultaneously showed that institutional support and expertise as well as self-efficacy had a positive effect. However, case management work experience, expertise (technology), and autonomy were found to have a negative effect during the stage of case management performance. Conclusions: As a result of the study, it was confirmed that raising the case manager's expertise and support from the institution and organization are important factors to improve the level of case management performance. The research also derived practical ways of reinforcement of case manager capacity, institutional and organizational support, operation of rehabilitation-case management teams, and occupational health-related aspects.

• Korean Journal of Adult Nursing
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• v.22 no.3
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• pp.260-270
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• 2010

Purpose: The main question is systematic review of the published in Korea and foreign countries on warming therapy for surgical patients. Methods: The researchers searched at Medline, CINAHL, KERIS, Adult Nursing Association, Korean Society of Nursing Science, Korean Academy of fundamentals of Nursing, and National Assembly Library web site for the published on warming therapy for surgical patients from 1980 to 2008. Words for search were operation/surgery, warming, operation/surgery and warming. Studies were included randomized controlled trial, and there were no restrictions regarding operative phase and outcome measures. Results: 36 published researches that met the criteria were mostly published in foreign countries between 2000 and 2008 and focused on surgery with general anesthesia. Sample size ranged from 21 to 60 subjects, age range between 21 and 60 years of age. Thirty different warming therapies were reported, fifty-two different dependent variables. Outcome indicators included active external warming, intra-operative, and body temperature. 'Positive effects' and 'no effects' equaled. The most frequently reported 'positive effects' were body temperature, shivering, and acid-base balance. No effects were more likely to be heart rate, blood pressure, and hemodynamics. Conclusion: Many types of warming therapy, are reported in the literature with little information about the efficacy of each, many different dependant variables were studied. There were no consistent reports as to length of time used for warming procedures. Overall, the effects of warming therapy are inconsistent. And additional research must be down before any particular method of warming can be used with confidence as to its effectiveness. Attention must be made as to the research design, better measurement of the dependent variables. This review may serve as a base.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.318-330
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• 2013

It is necessary to estimate the operating cost for constructing an urban railway system. The present study was thus carried out to develop an estimation function of the operating cost for a MRT(Medium-sized Rapid Transit) system. We selected seven independent variables that could influence the operating cost: the rolling stocks, the number of trains in operation, the length of the lines, the number of stations, the number of passengers per day, the frequency of train operation, and the number of depots. We performed a multiple regression using Excel. Three types of regression functions were thereupon developed. All of them proved to be appropriate after comparing the results of the estimated cost. It will therefore be possible to use one of these three types, depending on the assumptions of the independent variables.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4770-4777
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• 2011

Recently a rapidly changing business environment, business strong ability and operating an integrated information system is actively made. However, the result of the success factors affecting the overall project, but a study to analyze the project's success is not enough. In this study, the project implementation and operation of the critical success factors that can occur in the analysis of research and practice leading to the combination of variables derived from empirical studies find and isolate the success factors were over. Present study came from existing projects that can be the integrated system, representation factors affecting the implementation and operation of business processes in order to analyze the elements and procedures, performance capabilities of the organization, consultants and professionals involved with other related variables were analyzed by injecting. In this study, the consultants and experts showed that the variables are very significant rather than the organization's ability to perform business processes and procedures. This study will give a guideline as future success factors for building an integrated system of professional experiences.