• Journal of Advanced Marine Engineering and Technology
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• v.25 no.1
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• pp.191-198
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• 2001

In order to comprise a basic closed-loop control system for hydraulic systems it is necessary to detect the piston rod stroke of a hydraulic cylinder. There are many conventional type sensors which can detect the displacement of cylinders. However, they cannot reveal the original performance normally or they cannot be applied at all where the operating circumstance of cylinders is beyond specifications of sensors. Especially, for the purpose of detecting the strokes of cylinders mounted on heavy equipments, a special exclusive sensor must be used because the operating circumstances of heavy equipments are so severe that general purpose sensors cannot endure such circumstance as shock and a residual vibration induced by rough works. In this paper, an exclusive method for detecting the piston rod stroke for heavy equipments is suggested, which adopts a remote detecting technique using optical fiber sensors. Several experiments using the prototype are executed for verifying the effectiveness of the suggested method and the possibility of the accurate detection of stroke.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.5
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• pp.31-38
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• 2002

In this paper, we model a two-server queueing system with priority, to which we put a restriction on the number of servers for each customer class. customers are divided into two different classes. Class 1 customers have non-preemptive priority over class 2 customers. They are served by both servers when available but class 2 customers are served only by a designated server. We use a method of generating function depending on the state of servers. We find the generating function of the number of customers in queue, server utilization, mean queue length and mean waiting time for each class of customers.

• The Journal of Fisheries Business Administration
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• v.27 no.1
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• pp.1-13
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• 1996

The paper investigates the problems fishing industry will face when Far East countries like Korea, China and Japan establish their own exclusive economic zones to Protect their own interests. The expected problems of importance are as follows ; (1) tile issue of Dok - do possession between Korea and Japan, (2) the issue of continental shelf around the Korean peninsula, (3) the issue of the management of international and domestic fishing grounds. This paper suggests that, since these issues are very important for our country's future interest, the Government should organize a task-force team consisting of the specialists in related areas and fully use this team to establish economic and social systems appropriate to solve the Problems of fishing industry from a long-term perspective.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.19-26
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• 1997

The manufacture of an impeller typically requires the 5-axis CNC machining, since the impeller is usually under working conditions such as high speed, high temperature, and high pressure. Thus, this study contributes to development of an exclusive CAM system for effective 5-axis CNC machining of a ruled surface type impeller. In this study, the sampled impeller is made of blades and a body and the blade consists of ruled surfaces between hub curve and shroud curve. In the post processing for 5-axis NC part program, the cutter axis direction vector is the straighten vector on ruled surface. The position of ball center in ball end mill cutter is decided on the interference check between the cutter and body surface of impeller using with the modified z-map method that z-axis is the same of cutter axis direction vector. The exclusive CAM system for an impeller developed in this study was very effective for designs and 50-axis machining of a ruled surface type impeller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.59-64
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• 2002

Recently the applications of high speed machining are increasing due to the need for high performance and high accuracy machining and machining for difficult-to-cut material. However, the high speed machining also accompanies some problems: the product quality can be degraded due to the tool wear and the product cast can go up due to frequent tool replacements. Therefore, it is necessary to develop a technique of quantitative tool wear measurement to determine the precise timing for tool replacement. In this respect, this study suggests a reliable technique far the reduction of error components by developing a system using a CCD camera and an exclusive jig to be able to precisely measure the size of tool wear in flat end mill for high speed machining.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.12-15
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• 2001

A summation generator creates sequence from addition with carry of LFSR (Linear Feedback Shift Register) sequences. Similarly, it is possible to generate keystream by bitwise exclusive-oring on two FCSR sequences. In this paper, we described the cryptographic properties of a sequence generated by the FCSRs.

• Journal of Nutrition and Health
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• v.28 no.7
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• pp.636-643
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• 1995

This study was conducted to find some differences in infant feeding pattems between well educated Koreans and local populations living in Texas, USA. Initiation rate of exclusive breastfeeding in the hospital was 35.9% in Koreans and 60.4% in Americans. At 2, 4 and 6 months, exclusive breastfeeding rates were 34.0%, 20.8% and 13.2% for Koreans and 47.2%, 34.0% and 27.2% for Americans respectively. There was a significant difference in age of weaning from breast between these two groups(p<0.01). In Koreans the most common reason for the early termination before 4 months was maternal report of milk insufficiency. 55.6% of Koreans and 42.3% of Americans fed infants on scheduled rather on demand feeding. Primary sources of advice about feeding were medical professionals in Americans while baby's grandmother was the main source in Koreans. In Americans, choice of breastfeeding was not associated with ethnicity, maternal education, and family income in the study. Interventions to promote and support participants of Women Infants and Children(WIC) may play a role in Americans. It might be suggested that effective nutrition education programs targeting for Korean mothers to promote breastfeeding should be needed urgently and systematically.

• Journal of environmental and Sanitary engineering
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• v.19 no.3 s.53
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• pp.58-64
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• 2004

Biological treatment of wastewater was studied with a purpose to remove TOC by the reduction of water hardness. The optimal conditions of coagulant were determined by reaction time and amount of coagulant. Experimental results indicate that the biological treatment after physico-chemical treatment was found to provide very efficient removal efficiency in the process to treat the textile wastewater, including the carbon dioxide treatment. The combined process of carbonization in the physico-chemical treatment respectively was increased the removal efficiencies of $30.0\%$ in biological treatment in comparison with exclusive biological treatment. As a result, the treatment of hardness after carbonization had the best removal efficiency of approximately $60.0\%$. The removal efficiencies in the exclusive biological treatment using Bacillus subtilis and after carbonization were increased by $38.9\%\;and\;69.0\%$ respectively. The combined Bacillus subtilis-assisted biological treatment was determined to be the most effective method to treat the textile wastewater in an economic point of view, the water quality in the wastewater treatment plays an important role.

• The Journal of Fisheries Business Administration
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• v.36 no.2 s.68
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• pp.25-52
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• 2005

Since late 1990's, the Fish Aquiculture Households belong Fishing Community have been faced very serious pressure of management. The surface factors of this situation have been understood to overproduction and too much imports from China, but basic factor was caused structural problem, that is considered small scale production system. Then, We should enlarge scale of the Fish Aquiculture Households belong Fishing Community to overcoming profitability aggravation. To the Enlargement of Scale, We should consider to change the regime of Fishing Community that means two practical programs. First, it need to enlarge the scale of Fishing Community than now, and Second, it need to incorporate the Fishing Community for exclusive Management of Fish Aquiculture Rights.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.51.4-51
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• 2001

In order to comprise a basic closed-loop control system for a field robot it is necessary to detect the piston rod stroke of a hydraulic cylinder. There are mary conventional type sensors which can detect the displacement of cylinders. However, they cannot reveal the original performance normally or the cannot be applied at all where the operating circumstance of cylinders is beyond specifications of sensors. In this paper, an exclusive method for detecting the piston rod stroke is suggested, which adopts a remote detecting technique using optical fiber sensors. Several experiments using the prototype are executed for verifying the effectiveness of the suggested method and the possibility of the accurate detection of stroke.