• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.472-481
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• 2015

Objectives: Welding is a major task in shipbuilding yards that generates welding fumes. A significant amount of welding in shipbuilding yards is done on steel. Inevitably, manganese is present in the base metals being joined and the filler wire being used and, consequently, in the fumes to which workers are exposed. The objective of this work was to characterize manganese exposure associated with work area, total and particle size-selective mass concentration, and compare the mass concentrations obtained using a three-piece cassette sampler, size-selective impactor sampler and blood manganese concentrations. Materials: All samples were collected from the main work areas at one shipbuilding yard. We used a three piece cassette sampler and the eight stage cascade impactor sampler for the airborne manganese mass concentration of total and all size fractions, respectively. In addition, we used the results of health examination of workers sampled for airborne manganese. Results: The oder of high concentration of airborne manganese in shipbuilding processes was as follows; block assembly, block erection, outfitting installation, steel cutting, and outfitting preparation. The percentages of samples that exceeded the OES of the ministry of employment and labor by the cassette sampling method was 12.5%, however 59.1% of sampled workers by the impactor sampling method exceeded the TLV of the ACGIH. Conclusions: Even though the manganese concentrations in blood of workers exposed to higher airborne manganese concentration were higher than among those exposed to lower concentrations, there was no difference in blood manganese concentrations among work duration. The data analyzed here by characterizing size-selective mass concentrations indicates that the inhaled manganese of welders in shipbuilding yards could be mostly manganese-containing respirable particle sizes.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.1
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• pp.94-101
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• 2014

Recently, in order to reduce the time required to replace an optical jumper cord, many researchers are using a field-installable connector and applying the ferrule polishing method, ferrule mechanical contact method, or ferrule fusion contact method. However, the process of arranging the length of the optical fiber, i.e., inserting the optical fiber into the ferrule by hand and checking its cross section, takes 60% of the time required for the entire process, which increases the overall cost. Therefore, in order to make this task more cost-effective, we will develop an automated inspection system with automatic cross-sectional arrangement of a field-installable connector. This system will be able to decrease the failure rate from 10% to 2% compared with the conventional method when cutting the optical fiber inserted into the ferrule. It will also improve the productivity by decreasing the test time by 28% compared with the conventional method. Our studies showed that it was possible to reduce the production costs and improve the quality of a field-installable connector, and we expect it to dominate the market.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.604-610
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• 2007

Injection molding is the most common method of shaping plastic resins for manufacturing a variety of parts. This injection molding is accomplished by injection molding machines (IMM) which consists of a hewer, a reciprocating screw, barrel assembly, and an injection nozzle. The plastic resin is fed to the machine through the hopper and it should be heated to the target melting temperature, which depends on material properties, as closely as possible with very small temperature overshoot in the barrel. Since the barrel, which has temperature dependent specific heat and thermal conductivity in the operating temperature range, is heated by the several electric heater bands, it is not an easy task to control the temperature of the barrel owing to the interference of neighboring heaters and its material properties. Though PID controller with auto-tuning capability is widely adopted in the nm, the auto-tuning process should be carried out whenever the operating temperature is changed significantly. Recently, though the predictive controller is developed and shows good performance, it has drawbacks: 1. Since the heat transfer modeling process is very complicated and should be carried out again when the barrel is changed, it is somewhat inappropriate in the field. 2. The controller performance is not validated in whole operating temperature range. In this paper, cascade type simple PI controller with input restriction is proposed to find the possibility of controlling the barrel temperature in the whole operating temperature range. It is shown by experiment that the proposed controller shows good performance. This result can be applied to design of PI controller with auto-tuning capability.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.117-126
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• 2016

This study examined the relative effects of different feedback delivery method (face-to-face vs. e-mail) and reinforcement history on work performance. Participants were asked to work on a simulated mobile phone assembly task. They performed for 30 minutes per session and attended 4 sessions. The dependents variable was the percentage of correctly completed work tasks. Of 100 participants recruited, 50 had a reinforcement history and another 50 had no reinforcement history with the feedback provider in this study. The participants in each group were randomly assigned into two experimental conditions: face-to-face feedback and e-mail feedback. The results showed that for the participants who had reinforcement history, the two feedback delivery methods did not produce a significant difference in the percentage of correctly completed work tasks. However, for those who had no reinforcement history, the two feedback methods did produce a significant difference.

• Journal of Korean Library and Information Science Society
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• v.48 no.2
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• pp.23-51
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• 2017

This study aims to analyze and compare the components of school library laws of Korea and Japan. The laws of two nations were legislated by the members of the National Assembly, and NGO contributed significantly to the legislative process. The common parts of the two laws are objectives, definitions, responsibilities of nations, establishments, tasks, human resources, collaborative networks, and education, etc. For the task of school libraries, Korean law emphasizes the function of education, while the Japan law focuses on the basic duties of school libraries. In terms of human resources, school libraries in Korea can have a teacher librarian, a practice teacher, or a librarian, but in Japan, they can have either a teacher librarian or a school librarian. The Korea law specifies the aspects of facilities and materials, but the Japan law does not. Finally, for the educational role, the Korean libraries have reading and information literacy training that are parts of school curriculum, while the Japan libraries have only a library use guidance program and does not include reading education.

• Industrial Engineering and Management Systems
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• v.10 no.3
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• pp.197-202
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• 2011

In traditional production lines, such as assembly lines, each worker is usually assigned to a particular fixed work, and decreasing the task to master the assigned work is valuated. However, when an imbalance exists between workers' speeds, if a worker delays the overall work in the production line, the production rate of the particular line will also decrease. To avoid this problem, the "Self-Balancing Production Line" was introduced. In this type of production line, each worker is assigned work dynamically, and when specific conditions are satisfied, production remains balanced. Characteristics of these lines that can be preempted at any place have already been analyzed by some researchers. A previous paper examined the situation in which only a single worker can process one machine and cannot preempt processing, and the improved policy of an ordinary selfbalancing production line, which specifies which stations workers can process and how workers can behave. This policy achieveda high production rate with only four stations and two workers (Buzacott, 2002). In that paper, worker processing stations and the behavior of a specific worker were limited, andthe paper focused only on specific stations and workers. Therefore, it is not applicable to any worker sequence. In this paper, we focus on other ways to decrease cycle time. In this kind of line, a worker processes at his or her speed. Therefore, if a worker is assigned stations according to his or her speed, the line can decrease cycle time. To do so, we relax the assumptions of this type of line and set a new condition. Under these conditions, we compare our results to the results of previous papers.

• Archives of design research
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• v.4 no.1
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• pp.61-73
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• 1991

The exhibition activity that a company is rendering to their consumers for the purpose of advertisement, sales promotion and enhancement of company inage get more and more internationalized and specialized. A company is changing from mass production system to small quantity production of various kinds to meet consumer's individualization and differentiation. Also, a company is experiencing a major change in their marketing strategy. As the society is entering on Information Age, the contents that a company intends to give consumer may be different individually. If a consumer is informed wrong information of the goods, a company needs a place to meet consumer face to face where the consumer feels and understands the substance of the goods. This is the current characteristics of Exhibition Media. Based on the result of the current Special Exhibition home and abroad along with background and characteristics of special Exhibition, this study sets a following task reflecting the general trend of social, cultural and economic atmosphere. First, Current Exhibition Industry will be diversified into more Specialized Exhibition, while our Exhibition Industry is very shaky under severe international competition. Also, Exhibition Plan that involves with architecture, interior, graphic, industrial design and advertisement, etc., needs international competitiveness while enhancing identity of Exhibition Plan along with comprehensive marketing strategy in the future. Second, Among most of the local special Exhibitions which invite the general public are normally invited for company public relation contrary to those of U.S.A. and Europe. This signifies of our industrial and social structure's by-product. As the future exhibition become Information Com$$\mu$ication Exhibition which requires specialized technical explanation, the correct description of the goods should be set as a Judgement basis of Exhibition Plan. Third, In parallel with increase of the Exhibition, the equipment expenses of a company goes up continuously. In view of this, a study $$\mu$t be oriented for re-use and curtailment of expenditure of those equipment. Also, as the use of Assembly System B on the rise as a result of diversification of special Exhibition, a study on the development of new material & design for Exhibition Equipment only B required.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.105-110
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• 1990

In this paper, a compliance robot control algorithm using a PID adaptive controller is proposed. The compliance robot is suitable for the tasks in contact with environment, such as assembly operation or surface processing. A hybrid robot control method can control force and position simultaneously and two independant feedback closed loops are formed in this method. Because the compliance robot is operated in contact with environment, it is very difficult to obtain linear model of dynamics for this robot. In order to overcome this difficulty, a PID adaptive controller independant of robot dynamics is applied to the compliance robot. The proposed control algorithm for the compliance robot was analyzed and conformed by simulating the surface processing task by a two-joint robot.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.185-192
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• 2013

The purpose of this study is to set the relationship between each parts that forms the engine of an automobile based on the 3D visualization technology which is able to be learned according to the skill of the operator in the industry field and to recommend the auto parts using a task ontology. A visualization method was proposed by structuring the complex knowledge by signifying the link and the node in forms of a network and using SOM which can be shown in the form of 3 dimension. In addition, by using is-a Relationship-based hierarchical Taxonomy setting the relationship between each of the parts that forms the engine of an automobile, to allow a recommendation using a weighted value possible. By providing and placing the complex knowledge in the 3D space to the user for an opportunity of more realistic and intuitive navigation, when randomly selecting the automobile parts, it allows the recommendation of the parts having a close relationship with the corresponding parts for easy assembly and to know the importance of usage for the automobile parts without any special expertise.

• Convergence Security Journal
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• v.19 no.2
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• pp.123-128
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• 2019

In March 2016, the Korean National Assembly passed the Counterterrorism Act called as "Counterterrorism Law for the Protection of the People and Public Safety", and relevant functions and roles of the counterterrorism institution were granted based on the law. However, a number of problems have been raised in the course of the job performance of the counterterrorism related institution, and various improvements have been discussed. This study conducted 'Analytic Hierarchy Process(AHP)' on the experts to identify the issues related to the improvement possibilities of the counterterrorism system that had been discussed previously. The results of the analysis to improve the current counterterrorism system are as follows. First, the priorities of the top factors were identified as in the order of legal institutions, cooperation, and operational aspect. Next, the priorities of the individual sub-factors were identified as the reorganization of the counterterrorism task force, the organic cooperation of domestic counterterrorism institution, and the cultivation of specialized human resources for anti-terrorism work. It was found that we should discuss the reorganization of counterterrorism institution as a policy consideration to improve the counterterrorism system.