• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1038-1045
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• 1994

In this paper, algorithm and built-in test circuit for testing all PSF(Pattern Sensitive Fault) occuring in CAM(Content Addressable Memory) are proposed. That is, built-in test circuit that uses minimum additional circuit without external equipment is designed. Additional circuit consist`s of parallel comparator, error detector, and modified decoder for parallel testing. Besides, the study on eulerian path for effectiv test pattern is carried out simultaneously. Consequently, using proposed algorithm, we can test all contents of CAM with 325+2b(b:number of bits) operations regardless of number of words. The area occupied by test circuit is about 7.5% of total circuit area.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.46-53
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• 2016

In mobile communication systems, location management deals with the location determination of users in a network. One of the strategies used in location management is to partition the network into location areas. Each location area consists of a group of cells. The goal of location management is to partition the network into a number of location areas such that the total paging cost and handoff (or update) cost is a minimum. Finding the optimal number of location areas and the corresponding configuration of the partitioned network is a difficult combinatorial optimization problem. This cell grouping problem is to find a compromise between the location update and paging operations such that the cost of mobile terminal location tracking is a minimum in location area wireless network. In fact, this is shown to be an NP-complete problem in an earlier study. In this paper, artificial bee colony (ABC) is developed and proposed to obtain the best/optimal group of cells for location area planning for location management system. The performance of the artificial bee colony (ABC) is better than or similar to those of other population-based algorithms with the advantage of employing fewer control parameters. The important control parameter of ABC is only 'Limit' which is the number of trials after which a food source is assumed to be abandoned. Simulation results for 16, 36, and 64 cell grouping problems in wireless network show that the performance of our ABC is better than those alternatives such as ant colony optimization (ACO) and particle swarm optimization (PSO).

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.207-218
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• 2023

Duck farming restriction refers to a program in which duck farms suspend their operations for a certain period at times when the risk of avian influenza (AI) is high and receive compensation from the Korean government. This study analyzed the effect of this duck farming restriction on the incidence of AI using data on regional AI incidence rates, the program participation rate, and characteristics of poultry farming in 2016 (before the implementation of the restriction), as well as data from 2020 and 2021 (when new AI outbreaks occurred). In this study, the treatment group was divided into five subgroups according to the policy participation rate and a difference-in-difference (DID) estimation was conducted using certain covariates, in this case the average number of ducks raised, the land area, the number of high-susceptibility farms, the number of low-susceptibility farms, the average number of farms within a 3 km radius, the average distance to the nearest farm, and a year dummy. The results showed that when more than 30% of all duck farms in a region participated in the farming restriction, it had a statistically significant effect on the incidence of AI. Specifically, when more than 30, 40, 50, and 60% of all duck farms participated in the farming restriction, the AI incidence rate decreased by 0.7184, 1.0025, 1.5844, and 1.5843%p, respectively.

• Korean journal of communication and information
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• v.16
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• pp.7-35
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• 2001

This paper examined the present status of local newspapers and their problems. It was originated from the fact that the number of local newspapers have continuously increased since 1987 when the establishment of newspaper company became convenient, and that as a result the competition among local newspapers became high and several unexpected negative out comes brought forth. The analytical focus of this parer was placed on the internal and external environments surroundings local newspapers. The results showed followings: There are too many local newspapers competing each other in the same area; Financial crises mainly caused by over-competition are critical; Ownership and business operations are too distorted to take the socially expected role of newspapers; Many newspapers are often mobilized for the political and economic purposes of the owner; Market rules and advertising inducement practices are likely to be violated because of over-competition; the morales of Journalists are decreased and work qualities are deteriorated. On the basis of these findings this paper suggested several policy implications: The structure of ownership has to be changed into a direction where a few major stock-holders cannot influence the whole business operations; Top managers have to change their business motivation from profit-seeking to profit-sharing; business practices has to be open and clean; New editorial polices attracting readers have to be established; qualified Journalists have to be recruited and they have to be retrained throughout their career life.

• IE interfaces
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• v.16 no.4
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• pp.450-462
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• 2003

In this paper, we deal with a process and layout design for producing a planned amount of Sikhye in a given limited time period under a reasonable production schedule. We represent a Sikhye production line as a vector N, the element of which denotes the number of tanks required in each process and our objective is to find an appropriate vector which minimizes the total investment cost. We suggest a systematic method for finding an appropriate N and an appropriate layout to N. In detail, first, we decide the required sequence of processes and the required operations for each process and we estimate standard operating times. Second, constructing a precedence diagram, we find a critical path in order to reduce the total production lead time for a batch of Sikhye. Third, given a limited N space, we manage to construct manually each production schedule using both the processing times of the critical operations and transfer times. Finally, we find an optimal vector N which gives a minimum investment cost and meets both the time constraint and quantity constraint. In addition, with the estimated relative size of each tank, we suggest an appropriate conceptual layout design including an expansion area for future demands, based on the span technique used in the field of architectural design.

• Korean Journal of Computational Design and Engineering
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• v.14 no.1
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• pp.18-24
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• 2009

This paper proposes an analytical method of evaluating the maximum error by modeling the exact tool path for the tool traverse singular region in five-axis machining. It is known that the NC data from the inverse kinematics transformation of 5-axis machining can generate singular positions where incoherent movements of the rotary axes can appear. These lead to unexpected errors and abrupt operations, resulting in scoring on the machined surface. To resolve this problem, previous methods have calculated several tool positions during a singular operation, using inverse kinematics equations to predict tool trajectory and approximate the maximum error. This type of numerical approach, configuring the tool trajectory, requires much computation time to obtain a sufficient number of tool positions in a region. We have derived an analytical equation for the tool trajectory in a singular area by modeling the tool operation into a linear and a nonlinear part that is a general form of the tool trajectory in the singular area and that is suitable for all types of five-axis machine tools. In addition, we have evaluated the maximum tool-path error exactly, using our analytical model. Our algorithm can be used to modify NC data, making the operation smoother and bringing any errors to within tolerance.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.13-16
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• 2004

This paper deals with a one-searcher multi-target search problem where targets with different detection priorities move in Markov processes in each discrete time over a given space search area, and the total number of search time intervals is fixed. A limited search resource is available in each search time interval and an exponential detection function is assumed. The searcher can obtain a target detection award, if detected, which represents the detection priority of target and is non-increasing with time. The objective is to establish the optimal search plan which allocates the search resource effort over the search areas in each time interval in order to maximize the total detection award. In the analysis, the given problem is decomposed into intervalwise individual search problems each being treated as a single stationary target problem for each time interval. An associated iterative procedure is derived to solve a sequence of stationary target problems. The computational results show that the proposed algorithm guarantees optimality.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.16-21
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• 2007

Along with the opening of the high speed railroad in 2004, the number of long tunnels constructed is increasing and will be continued. In this respect, the fro inside the tunnels is a main cause of drastic damages to both facilities and lives of passengers on board, especially more severe consequences are expected if the fire occurs on a train in urban area. Even though, the threat to human lives due to the increasing number of tong tunnels and increasing train operation times inside such tunnels is getting bigger, the studies to measure safety of the tunnel and to enhance the safety of passengers have not been carried out enough in Korea. Therefore, in this paper, we will use the probabilistic method to predict the average number of deaths of passengers in case of fire on a train iii tunnel, and show the potential risk to passengers which can be a guide for safer design of tunnels to be constructed.

• Journal of Chest Surgery
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• v.49 no.sup1
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• pp.53-59
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• 2016

Background: The purpose of this study is to evaluate the concentration of cardiovascular surgical procedures in a metropolitan area and investigate the perception of specialists regarding governmental policies to resolve this imbalance. Methods: From March to May 2015, surveys were distributed to members of the Thoracic and Cardiovascular Surgery Association. The final pool of research subjects consisted of 75 respondents. Subjects were queried regarding the concentration of cardiovascular operations in metropolitan areas, alternatives to the imbalance, and governmental policies to resolve the inequalities. Results: Survey participants responded that South Korea needs governmental policies to alleviate the concentration of cardiovascular surgery patients in large metropolitan hospitals. Participants agreed that the freedom to choose medical institutions and improved accessibility to metropolitan hospitals due to advanced transportation systems were some of the causes for the concentration. A majority (98.7%) of respondents thought establishing thoracic and cardiovascular surgery centers in provinces was an appropriate solution to alleviate the concentration. Thoracic and cardiovascular surgery specialists were ranked as the number one group on which to focus development. Conclusion: Developing and carrying out policies to establish thoracic and cardiovascular surgery centers in provinces will alleviate the regional imbalance in available heart surgery services and an overall improvement in cardiovascular disease treatment in South Korea.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.57-66
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• 2009

Zigbee is a universal communication standard used in USN and is utilized in various applications. Zigbee protocol provides an address within a single PAN network, and at this time, it uses DAA. This is a method that divides a 16-bit address area into blocks with a fixed size according to the depth to assign one to each node. However, this method is limited because it has to assign addresses in 16 bits. As the depth increases, the number of nodes also increases exponentially to the maximal number of routers provided to each depth. Therefore, it is difficult to construct a huge network with numerous routers and large depth as in the places which are wide or have many shadow areas. Besides, since all the operations are performed in a single PAN network, it is hard to make several PANs into a single network. This article suggests new addressing and routing methods that can construct several PAN networks into a single network and combine broad area with less limitation in the number of routers and depth by extending the Zigbee-based network. Moreover, this paper has tested its performance and has verified its usability through substantive tests.