• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.789-798
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• 2002

Even when users are moving, a major problem in such a mobile networks is how to locate mobile clients. Two major operations are involved in managing a mobile client's location : the location registration operation and the call tracking operation. The past methods can only minimize the cost of one of these two operations, but not both. The contribution of this paper is to propose strategy that minimize the costs of both operations simultaneously. Our performance analysis proves that the proposed strategies are superior to the past methods.

• The Journal of Information Technology
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• v.8 no.3
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• pp.1-10
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• 2005

Cosine and Sine function is widely used for the arithmetic, translation, object drawing, Simulation and etc. of Computer Graphics in Natural Science and Engineering. In general, Cordic Algorithm is effective method since it has relatively small size and simple architecture on trigonometric function generation. However profitably it has those merits, the problem of operation speed is occurred. In graphic display system, the operation result of object drawing is quantized and has the condition that is satisfied with rms error less than 1. So in this paper, the proposed generator is composed of partition operation at each ${\pi}/4$ and basic Cosine, Sine function generator in the range of $0{\sim}{\pi}/4$ using the lower order of Tayler's series in an acceptable error range, that enlarge the range of $0{\sim}2{\pi}$ according to a definition of the trigonometric function for the purpose of having a high speed Cosine, Sine function generation. And, division operator using code partition for divisor three is proposed, the proposed function generator has high speed operation, but it has the problems in the other application parts with accurate results, is need to increase the speed of the multiplication.

• Journal of Chest Surgery
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• v.22 no.5
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• pp.753-759
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• 1989

Recently, the arterial switch operation has received more interest and increased application for many patients with TGA [Transposition of the Great Arteries]. Not all patients, however, are suitable candidates for this approach, and its success will be measured against the Senning procedure. From June 1982 through June 1989, 48 consecutive patients underwent correction of TGA by a modification of the Senning procedure in our hospital. 34 were males and 14 females, with ages ranging from 3 months to 99 months [mean age 14 months]. The patients were divided into two groups, group I [TGA with intact ventricular septum or without significant pulmonary hypertension] and group II [TGA with significant pulmonary hypertension]. The hospital mortality was 9.5 % in group I and 55.6 % in group lI. 31 patients were discharged from the hospital after a Senning operation and have been followed a mean of 31.2 months. There were 5 late deaths, 3 in group I and 2 in group II. All patients were followed up with EKG, echocardiogram, and in several cases, Holter monitor and cardiac catheterization and angiography were also performed. There have been arrhythmias in 7, superior vena caval obstruction in 5, pulmonary venous obstruction in 2 and tricuspid insufficiency and/or right ventricular dysfunction in 16 patients. The Senning operation for Simple TGA can be performed with a low operative mortality and morbidity, but tricuspid insufficiency and/or depressed right ventricular function can be a problem with prolonged follow up.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.69-77
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• 2019

Among the main functions of the grid-connected photovoltaic (PV) system, the anti-islanding operation function is a very important problem. Recently, due to the improvement in power generation efficiency and the maintenance advantages in PV system, the use of string inverter has increased so that the possibility of islanding operation has been raised. Generally, when a power system faults, the PV inverter must be disconnected from power system within 10 cycles by the anti-islanding operation function. However, in the real-time of power system, the output power of the PV system within 10cycles is effected. In this paper, we analyzed the effect of grid-connected PV system on power quality in a short time within 10 cycles on fault case of power system using the Matlab Simulink program.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.31-41
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• 2005

Currently many Traffic Management Centers(TMC) have been constructed, there are in the process of operating and propelling. Although many TMC are constructed up to now, we have no discussion about positive operation plan and no many studies. We consider that the center should foster many experts for a qualitative development. So we provides to analysis internal and external operation system of UC and to Present the solution about a problem of government subject and an adequate scale of operation system. Also we Present a drawing up plan about regular and occasional educational plan and operation manual for activating the educational system. We suggest that many TMC and government should pay attention to those issues and invest money in operation issues and researches.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.11
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• pp.955-962
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• 2016

In recent years, there have been emerging needs for standardized software-based motion application development for better scalability and support for multiple operation modes for small quantity batch production. Although a software-based motion system provides a basis for constructing multiple operation modes on a machine, it is not easy to construct such systems without tools for defining multiple motion operation modes and standardized mode-change protocols. This paper proposes a motion recipe concept to overcome this problem; the concept includes the authoring of multiple motion operation modes using the PLCopen-compliant motion function blocks and communication protocols to trigger operation mode changes from an external interface. The motion recipe was implemented by extending an IEC 61131-3 compliant IDE called Beremiz, and the correctness of the motion recipe-based application behavior was verified on a real testbed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.169-170
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• 2020

Although Busan Port is a world-class transshipment port, it is geographically divided and, despite the continuous increase in transshipment volume, ITT port integrated operation is not being performed, reducing port operation efficiency. In addition, the operation raises the problem of inefficiency in social and economic aspects, along with an increase in the volume of transshipment transport and the resulting increase in transshipment transport costs. This paper deals with the necessity of forming an integrated operation organization to carry out the ITT joint dispatch in the process of improving the ITT efficiency in Busan Port, and the organization structure centering on the transport companies and freight owners performing the Busan Port ITT. We intend to make a proposal for the establishment of an integrated operation organization in the form of a consortium and support plans. In addition, through analysis of implications, the role of the ITT stakeholders in Busan Port and related organizations will be addressed.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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• pp.1097-1108
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• 2023

Recently, demand for technology for energy economy and stable supply is increasing due to the increase in power demand of loads. The amount of DC power generation using new and renewable energy is noticeably increasing, and the use of DC power supplies is also increasing due to the increase in electric vehicles and digital loads. During parallel operation to increase the capacity of the power converter, the module bus method or the method using Can communication and serial communication has significant difficulties in smooth operation due to communication time delay for information sharing. Synchronization of information sharing of each power converter is essential for smooth parallel operation, and minimization of communication time delay is urgently needed as a way to overcome this problem. In this paper, a new communication method using pulse width information is proposed as a communication method specialized for parallel operation of power converters to compensate for the disadvantage of communication transmission delay in the existing system. The proposed communication method has the advantage of being easily implemented using the PWM and Capture function of the microcomputer. In addition, the DC/DC converter for DC distribution was verified through simulation and experiment, and it has the advantage of easy capacity expansion when applied to parallel operation of various types of power converters as well as DC/DC converters.

• East Asian mathematical journal
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• v.40 no.2
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• pp.183-207
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• 2024

This study is a case study that considered fractional senses and fraction operation abilities for 107 gifted students in elementary school classes. In order to find out the fractional sense, in the first question comparing the sizes of fractions 2/3 and 4/5, the students showed a variety of strategies, but the utilization rate of strategies excluding reduction to a common denominator did not exceed 50%. The second question can be solved by using the first question. It is a problem of finding two fractions by selecting four from six numbers 1, 3, 4, 5, 6, and 7 to create two fractions of which sum does not exceed 1. The percentage of correct answers to this question was about 27% (29 out of 107). Only 5 out of 29 students found answers using the first question, and the rest of the students sought answers through trial and error in various calculations. It shows that the item arrangement method from a deductive perspective has no significant effect on elementary school students. The percentage of correct answers was about 27% in the questions to find out the fraction operation ability-the question of drawing a 4/3 bar using a given 3/8-sized bar and 30.7% (23 out of 75) of the students who had wrong answers showed insufficient splitting operation. In addition, it has been shown that the operation of partitioning and iterating to form numerical senses and fractional concepts related to the fractions of the students has no significant impact.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.37-44
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• 2001

This paper describes the modeling of work environment for the extraction of abstract operation rules for cooperative work with multiple agent. We propose the modeling method using a potential field. In the method, it is applied to a box pushing problem, which is to move a box from a start to a goal b multiple agent. The agents follow the potential value when they move and work in the work environment. The work environment is represented as the grid space. The potential field is generated by Genetic Algorithm(GA) for each agent. GA explores the positions of a potential peak value in the grid space, and then the potential value stretching in the grid space is spread by a potential diffusion function in each grid. However it is difficult to explore suitable setting using hand coding of the position of peak potential value. Thus, we use an evlolutionary computation way because it is possible to explore the large search space. So we make experiments the environment modeling using the proposed method and verify the performance of the exploration by GA. And we classify some types from acquired the environment model and extract the abstract operation rule, As results, we find out some types of the environment models and operation rules by the observation, and the performance of GA exploration is almost same as the hand coding set because these are nearly same performance on the evaluation of the consumption of agent's energy and the work step from point to the goal point.