• IE interfaces
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• v.18 no.2
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• pp.136-147
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• 2005

This paper introduces a simulation study regarding the operation of the Painted Body Storage (PBS) in an automobile factory. In the paint shop of the factory, same colored bodies are grouped together in order to increase the effectiveness of process, for example decrease the loss of cleaning the painting-gun when the color of body changes from one to another. However the production of automobiles in the assembly shop is a typical example of the mixed model assembly production. Therefore PBS locates between the paint shop and the assembly shop for control the input sequence of bodies to the assembly shop, and it enables to meet the smoothing requirement of assembly sequence. There are highly restricted constraints on the assembly sequence in a assembly shop. Those are spacing restriction and smoothing restriction. If such restrictions are violated, conveyor-stop or utility work will be necessary. Thus the major objective of PBS is to control the assembly sequence in a way to meet the two restrictions. In this paper a case study of PBS in an automotive factory is introduced. The storage/retrieval algorithms are suggested and the proposed system is verified using simulation models. Sensitivity analysis for operating factors is also conducted.

• Journal of the Korean Institute of Navigation
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• v.24 no.1
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• pp.23-34
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• 2000

The human error or error involved with human is still the major portion of the causes of marine casualties and attracting a great concern in ship operation. However, there are not so many researches conducted to investigate or develop methodologies for analyzing such causes of human error in maritime industry, which may be caused by the variety of factors affecting the performance of ship operation and the characteristics of human being. This paper aims to study the methodologies used in investigating human factors or errors in maritime field through the investigation of researches performed so far. The methodology for human factors can be usually classified into one of three types; descriptive studies, experimental research and evaluation research. Also there are many different kinds of applied researches for some specific subjects. Prior to the investigation of the root cause of marine accident related with human error, clear concept of the human factors and systematic taxonomy shall be established. Moreover, it is very important considerations in case of casualty inspection on human factors that the inspector on the accident shall have adequate knowledges, understandings on the concept of human factors including the way of research more than those of methodologies and techniques.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.2
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• pp.248-257
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• 2014

As observed in the recent war, suppression of enemy air defense operation is one of the major tactics, simultaneously conducted with high payoff target. Specifically, our air defense operation should be properly constructed, since the operating environment of our forces mostly consists with mountainous terrain, which makes detections of the enemy difficult. The effective arrangements of low altitude air defense radars can be suggested as a way of improving the detection capability of our forces. In this paper, we consider the location problem of low altitude air defense radar, and formulate it as an Integer Programming. Specifically, we surveyed the previous researches on facility location problems and applied two particularly relevant models(MCLP, MEXCLP) to our problem. The terrain factor was represented as demand points in the models. We verified the optimal radar locations for operational situations through simulation model which depicts simple battle field. In the simulation model, the performance of optimal radar locations are measured by the enemy detection rate. With a series of experiments, we may conclude that when locating low altitude air defense radars, it is important to consider the detection probability of radar. We expect that this finding may be helpful to make a more effective air defense plan.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.121-126
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• 2017

EES System support to maximize equipment efficiency by providing real-time information of main equipment which has a significant effect on product quality and productivity, and to prevent equipment failure by detecting equipment abnormality in advance. Smart Equipment Engineering System(S-EES) integrates the activities performed at equipment that are the core of production activities and manages them by system so as to maximize the efficiency of equipment and raise the quality level of products to one level. In other words, when the product is put into the equipment, the recipe is downloaded through the RMS, the recipe is set to the optimal condition through R2R(process control), and the system detects and controls the abnormality of the equipment during operation through the FDC function in real time it means. In this way, we are working with the suitable recipe that matches the lot of product, detecting the abnormality of the equipment during operation, preventing the product from being defective, and establishing a system to maximize the efficiency through real-time equipment management. In this study, we review the present status and problems of equipment management in actual production lines, collect the requirements of the manufacturing line for the PCB line, design and develop the system, The measurement model was studied.

• Journal of Power Electronics
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• v.19 no.1
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• pp.68-78
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• 2019

The emergence of high voltage conversion applications has resulted in a trend of using semiconductor device series associations. Series associations allow for operation at blocking voltages, which are higher than the nominal voltage for each of the semiconductor devices. The main challenge with these topologies is finding a way to guarantee the voltage balance between devices in both blocking and switching transients. Most of the methods that have been proposed to mitigate static and dynamic voltage unbalances result in increased losses within the device. This paper introduces a new series stack topology, where the voltage unbalances are reduced. This in turn, mitigates the switching losses. The proposed topology consists of a circuit that ensures the soft switching of each device, and one auxiliary circuit that allows for switching energy recovery. The principle for the topology operation is presented and experimental tests are performed for two modules. The topology performs excellently for switching transients on each of the devices. The voltage static unbalances were limited to 10%, while the activation/deactivation delay introduced by the lower module IGBT driver takes place in the dynamic unbalances. Thus, the switching losses are reduced by 40%, when compared to hard switching configurations.

• Journal of Drive and Control
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• v.16 no.2
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• pp.15-21
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• 2019

In this study, the maximum system efficiency of the electro-hydrostatic actuators was experimentally investigated, where small size external gear pumps with volumetric displacement under 1.3 cc/rev were combined with a 400W servomotor as the prime mover. Since the efficiency data of the servomotor, gear pumps and hydraulic cylinder were not provided by the suppliers, experimental apparatuses for their efficiency measurement were extra built up. When a gear pump with a volumetric displacement of 1.27cc/rev was used on an electro-hydrostatic actuator system, the maximum system efficiency was not higher than 70%. This was because the most effective operation ranges of the motor and pump did not coincide each other. In order to match their operation ranges as one of the most crucial design factors, a speed reduction mechanism can be used, such as a timing belt. It was shown in the study that the maximum system efficiency could be increased from 70% to 76% in that way.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.134-142
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• 2002

Quadtree, which is a hierarchical data structure, is a very important data structure to represent binary images. The linear quadtree representation as a way to store a quadtree is efficient to save space compared with other representations. Therefore, it has been widely studied to develop efficient algorithms to execute operations related with quadtrees. The window operation is one of important geometry operations in image processing, which extracts a sub-image indicated by a window in the image. In this paper, we present an algorithm to perform the window operation of binary images represented by quadtrees, using three-dimensional $n{\times}n{\times}n$ processors on RMESH(Reconfigurable MESH). This algorithm has constant-time complexity by using efficient basic operations to route the locational codes of quardtree on the hierarchical structure of $n{\times}n{\times}n$ RMESH.

• Advances in pediatric surgery
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• v.9 no.1
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• pp.1-5
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• 2003

Preauricular sinus and preauricular skin tag are common childhood congenital anomalies. It is important for the pediatric surgeon to be familiar with the embryology and differentiation of head and neck structure to accurately diagnose and treat these lesions. Seventy eight patients with preauricular sinus and twenty-eight with preauricular skin tag treated in the Department of Pediatric Surgery at Hanyang University Hospital from January 1981 to May 2002 were reviewed to determine relative frequency, clinical classification and appropriate treatment. The male to female ratio of preauricular sinus was 1:1.2, and preauricular skin tag was 1:1. The most commonly presenting age of sinus and skin tag was before 5 year (62.8%) and before 1 year (53.6%). Twenty nine of 78 cases of preauricular sinuses were on the left, 25 on the right and 24 bilateral. Signs of infection were seen in 73.0% of patients with preauricular sinus at operation. Only 31.3% of lesions were infected in patients less than one year of age, but 89.5% between 3-5 years and 100% between 5-8 years. Cartilage was present in five patients with preauricular skin tag. Although re-operation due to wound infection was necessary in four cases, no recurrences were found. The preauricular sinus is a common anomaly in childhood, and has had a relatively high recurrence rate. But most of the recurrences were due to incomplete resection because of combined infection. Initial proper diagnosis and early operation are very important. Identification of the exact anatomical location of sinus tract is necessary because total excision of the lesions including those tracts is the only way to prevent recurrence.

• Quality Improvement in Health Care
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• v.26 no.2
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• pp.66-76
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• 2020

Purpose:Hospitals provide top medical service using exceptional manpower, medical technology, and state-of-the-art equipment, thus raising the standard of customer satisfaction. In addition, their medical service is becoming higher than before. One-stop service is a good way to improve the quality of customer-centered service as a qualitative marketing strategy. This study thus aims to facilitate subsequent research and compare customer satisfaction before and after one-stop service. Methods: The study included 72 patients who received the reserved examination and one-stop service for 20 days from April 23 to May 12, 2014. The surveyed questionnaire data were analyzed using SPSS 18.00. Results: The comparison results of customer satisfaction showed that the satisfaction score was generally high in the areas of kindness of examination staff, the speedy/accuracy of work processing of examination staff, and the kindness of reservation staff. The group before one-stop service showed their dissatisfaction with repeated visits and difficulty of booking a desired day. The group after one-stop service showed dissatisfaction with the long waiting time for examination or same-day treatment. Conclusion: The one-stop service showed good results, but new uncomfortable issues for the customer were revealed as well, which may result in more work of employees. Considering the characteristics of various clinical departments, the author hopes to find an efficient operation plan through the development and improvement of an appropriate one-stop service method.

• International Journal of Advanced Culture Technology
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• v.6 no.2
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• pp.117-122
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• 2018

As evidenced through rapidly growing digital repositories and web resources, automatic metadata generation is becoming ever more critical, especially considering the costly and complex operation of manual metadata creation. Also, automatic metadata generation is apt to consistent metadata application. In this sense, metadata quality and interoperability can be enhanced by utilizing a mechanism for automatic metadata generation. In this article, a mechanism of automatic metadata extraction called ExMETA is introduced in order to alleviate issues dealing with inconsistent metadata application and semantic interoperability across ever-growing digital collections. Conceptual graph, one of formal languages that represent the meanings of natural language sentences, is utilized for ExMETA as a mediation mechanism that enhances the metadata quality by disambiguating semantic ambiguities caused by isolation of a metadata element and its corresponding definition from the relevant context. Hence, automatic metadata generation by using ExMETA can be a good way of enhancing metadata quality and semantic interoperability.