• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.3
• /
• pp.83-89
• /
• 2016

The group formation problem of the machine and part is a critical issue in the planning stage of cellular manufacturing systems. The machine-part grouping with alternative process plans means to form machine-part groupings in which a part may be processed not only by a specific process but by many alternative processes. For this problem, this study presents an algorithm based on self organizing neural networks, so called SOM (Self Organizing feature Map). The SOM, a special type of neural networks is an intelligent tool for grouping machines and parts in group formation problem of the machine and part. SOM can learn from complex, multi-dimensional data and transform them into visually decipherable clusters. In the proposed algorithm, output layer in SOM network had been set as one-dimensional structure and the number of output node has been set sufficiently large in order to spread out the input vectors in the order of similarity. In the first stage of the proposed algorithm, SOM has been applied twice to form an initial machine-process group. In the second stage, grouping efficacy is considered to transform the initial machine-process group into a final machine-process group and a final machine-part group. The proposed algorithm was tested on well-known machine-part grouping problems with alternative process plans. The results of this computational study demonstrate the superiority of the proposed algorithm. The proposed algorithm can be easily applied to the group formation problem compared to other meta-heuristic based algorithms. In addition, it can be used to solve large-scale group formation problems.

• Journal of Korean Institute of Industrial Engineers
• /
• v.24 no.4
• /
• pp.559-569
• /
• 1998

Cellular manufacturing system (CMS) has been recognized as an alternative to improve manufacturing productivity in conventional batch-type manufacturing systems through reducing set-up times, work-in-process inventories and throughput times by means of group technology. Most of the studies on the design of CMS assumed that each part has a unique process plan, and that its demand is known as a deterministic value despite of the probabilistic nature of the real world problems. This study suggests an approach for designing CMS, considering both alternative process plans and uncertain demand. A mathematical model is presented to show how to minimize the expected amortized and operating costs satisfying these two relaxations. Four heuristic algorithms are developed based on tabu search which is well suited for getting an optimal or near-optimal solution. Example problems are carried out to illustrate the heuristic algorithms and each of them is compared with the deterministic counterpart.

• Asian Journal of Atmospheric Environment
• /
• v.8 no.1
• /
• pp.59-68
• /
• 2014

The Fukushima nuclear accident in 2011 had an extensive impact on the national electricity plans. This paper outlines alternative electricity scenarios that meet the goals of nuclear phase-out and greenhouse gas (GHG) emission reduction. This paper also analyzes the results of each scenario in respect to the electricity mix, GHG emissions, costs and employment effects. The Long-range Energy Alternatives Planning system (LEAP) model was used to simulate the annual electricity demand and supply system from 2011 to 2030. The reference year was 2009. Scenarios are reference (where existing plans are continued), A1, A2, B1, B2, and C2 (where the levels of demand management and nuclear phase-out are different). The share of renewable energy in the electricity mix in 2030 for each scenario will be increased from about 1% in 2009 to 8% in the reference scenario and from 11% to 31% in five alternative scenarios. Total cumulative cost increases up to 14% more than the reference scenario by replacing nuclear power plants with renewable energy in alternative scenarios could be affordable. Deploying enough renewable energy to meet such targets requires a roadmap for electricity price realization, expansion of research, development and deployment for renewable energy technologies, establishment of an organization dedicated to renewable energy, and ambitious targets for renewable energy.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.11 no.17
• /
• pp.67-80
• /
• 1988

This study is concerned with the comparison of two time homogeneous Poisson processes. Traditionally, the methods of testing equality of Poisson processes were based on the binomial distribution or its normal approximations. The sampling plans used in these methods are to observe the processes concurrently over a predetermined time interval, possibly different for each process. However, when the values of the intensities of the processes are small, inverse type sampling plans are more appropriate since there may be cases where only a few or even no events are observed in the predetermined time interval. This study considers 9 inverse type sampling plans for the comparison of two Poisson processes. For each sampling plans considered, critical regions and the design parameters of the sampling plan are determined to guarantee the significance level and the power at some values of the alternative hypothesis. The Problem of comparing of two Weibull processes are also considered.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.28 no.2
• /
• pp.158-165
• /
• 2018

Objectives: We analyzed the problems that work environment measurement results don't lead to workplace improvement in the Work Environment Measurement System to propose an alternative. Methods: We reviewed reports and articles written by the Korea Occupational Safety and Health Agency and academic circles to identify the problems in the current Work Environment Measurement System and suggest an alternative. Results: One of the reasons that the Work Environment Measurement has not resulted in workplace improvement is that there were no proper regulating systems for managing the workplace improvement plans or improvement results. Moreover, there are not enough professional manpower in ministry of labor to evaluate the improvement plans and results from the Work Environment Measurement. Therefore, all of the workplace whose Work Environment Measurement results exceed the occupational exposure limit (OEL) should be managed by regional ministry of labor, and outside experts and new system for verifying improvement are needed. Conclusions: To accomplish the purpose of Work Environment Measurement, it is necessary to improve the work environment according to the results of Work Environment Measure. For this, it is necessary for the government to manage the fulfillment of workplace improvement plans and for measurement agencies to secure expertise.

• Journal of the Korean Society for Library and Information Science
• /
• v.34 no.2
• /
• pp.47-67
• /
• 2000

This study is to evaluate the performance and suggest alternative plans of the public libraries in Taegu Metropolitan City. Regression analysis is used to fit a log-log equation to the total budget-output for all the public libraries. The results of the performance evaluation confirm that there is diseconomies of scale in library operations(${\Sigma}b_n$ 3,732). Therefore, all the public libraries should be improve productivity by restructuring of library identity, rational selection of physical sites and new branch library planning, userbased budget allocation and collection development, staffing and reengineering, optimalization of web site, and enforcement of service functions, etc.

• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.3
• /
• pp.281-288
• /
• 2001

We consider in this article a multi-objective part-machine grouping problem in which parts have alternative process plans and expected annual demand of each part is known. This problem is characterized as optimally determining part sets and corresponding machine cells such that total sum of distance (or dissimilarity) between parts and total sum of load differences between machines are simultaneously minimized. Two heuristic algorithms are proposed, and examples are given to compare the performance of the algorithms.

• Journal of the Korean Solar Energy Society
• /
• v.24 no.3
• /
• pp.85-92
• /
• 2004

Environmental issues become one of today's central concerns due to draining natural resources and environmental pollution. Architecture is given a great deal of weight on the evoking environmental pollution. In this point of view, polluting factors in architectural planning and construction were predicted in advance and alternative plans were studied, In investigation of alternative plans, both environmental pollution and economical efficiency of various alternatives were considered. A office building was analyzed for energy consumption and construction environmental load by appling LCA. Applying LCA to a office building includes a total amount of materials and energy consumption, environmental impacts and economical efficiency evaluation. In present study, LCA applied to electrical part of a office building and economical efficiency evaluation was considered.

• Journal of Korean Institute of Industrial Engineers
• /
• v.24 no.4
• /
• pp.551-558
• /
• 1998

In this paper, a job shop scheduling system is developed which can cope with the changes of shop floor status with flexibility. This system suggests near optimal sequence of operations by using Genetic Algorithm which considers alternative process plans. The Genetic Algorithm proposed in this paper has some characteristics. The mutation rate is differentiated in order to enhance the chance to escape a local optimum and to assure the global optimum. And it employs the double gene structure to easily make the modeling of the shop floor. Finally, the quality of its solution and the computational time are examined in comparison with the method of a Simulated Annealing.

• KIEAE Journal
• /
• v.7 no.5
• /
• pp.3-11
• /
• 2007

Nowadays, housing density in a city is getting higher, and this trend is expected to continue in the future. Therefore, Skyscraper is considered as future alternative architecture beyond symbolic meaning in aspect of demand and supply of urban land. However, skyscrapers which were newly built in Korea have many problems such as consumption of enormous amounts of energy, destruction of natural environment, and traffic jam. And from now on, environment-friendly development of skyscraper is urgently needed. However, plans or evaluation standards, which take account of the environment-friendly aspect of skyscraper, leave much to be desired. And especially it is hard to find environment-friendly skyscrapers. Therefore, this study aims to find realistic alternative solutions of environment-friendly skyscraper through analysis of the works of Ken Yeang who has been known as bio-climatic architect and tried to apply environment-friendly plans to skyscraper.