• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5B
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• pp.532-541
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• 2009

The RFID technology has attracted much attention these days due to the far better efficiency than the bar-code and magnetic card system. As an important usage, the 433 MHz active RFID tag was already adopted to the container ports in the United States and Europe for container loading/unloading automation and equipment location. However, there is one problem to be solved for the complete automation. RFID readers support only the direct communication with tags within their RF communication range. Then there are a lot of containers and equipments such as crane, yard tractor, and forklift in ports; and because they are made of metal, they interfere the RF communication, resulting in the occurrence of the dead-zone. In the dead-zone, RFID tags cannot receive any signal from readers. There may be several solutions to resolve the dead-zone problem. Among them, this paper suggests the most economical solution where RFID tags in the dead-zone can communicate with readers via neighbor tags in the multi-hop manner The new RFID communication architecture should be carefully designed in order to maintain the compatibility with the previous standard. Our experiment shows that the proposed architecture works well even in the case where some tags are out of the RF range of reader.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.682-689
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• 2014

Due to explosive growth of mobile data traffic, many kind of techniques based on small cell is proposed as solution for phenomenon. However, those techniques essentially demands increase of backhaul capacity and causes performance degradation if not satisfied. Based on that, the approach applying the storage capacity in place of backhaul capacity, which is known as femto-caching, is proposed to reduce data downloading delay of users in system. In this paper, we expanded previous research by proposing file placement strategy with distribution of user position, which is more practical scenario. Simulation results verify that our proposed scheme has better performance gains mainly because when coverage of helpers are overlapped, users get more opportunity to connect various helpers which enables users to download a variety kind of files from helpers, not base station.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.6
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• pp.264-273
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• 2006

In this paper, we propose a new architecture of Self-Organizing Fuzzy Polynomial Neural Networks (SOFPNN) by means of consecutive optimization and also discuss its comprehensive design methodology involving mechanisms of genetic optimization. The network is based on a structurally as well as parametrically optimized fuzzy polynomial neurons (FPNs) conducted with the aid of information granulation and genetic algorithms. In structurally identification of FPN, the design procedure applied in the construction of each layer of a SOFPNN deals with its structural optimization involving the selection of preferred nodes (or FPNs) with specific local characteristics and addresses specific aspects of parametric optimization. In addition, the fuzzy rules used in the networks exploit the notion of information granules defined over system's variables and formed through the process of information granulation. That is, we determine the initial location (apexes) of membership functions and initial values of polynomial function being used in the premised and consequence part of the fuzzy rules respectively. This granulation is realized with the aid of the hard c-menas clustering method (HCM). For the parametric identification, we obtained the effective model that the axes of MFs are identified by GA to reflect characteristic of given data. Especially, the genetically dynamic search method is introduced in the identification of parameter. It helps lead to rapidly optimal convergence over a limited region or a boundary condition. To evaluate the performance of the proposed model, the model is experimented with using two time series data(gas furnace process, nonlinear system data, and NOx process data).

• Journal of the Economic Geographical Society of Korea
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• v.7 no.1
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• pp.29-43
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• 2004

In this paper, we tries to investigate whether there are some differences of the characteristics between venture business in the metropolitan area and in the local area. We set up some hypotheses on the regional characteristics of venture business and test those using the raw data of Small and Medium Business Administration (SMBA) survey on the management of venture business. Our main findings are as follows: First, we analyze the industrial composition of ventures by region and find that in the metropolitan area high-technology venture business which is belong to software, or information, or communication industries is given much weight. But in the provinces, ventures belong to traditional manufacturing industries is given much weight. Second, we compared the characteristics of business network by region and find that the ventures in the metropolitan area are active in technical cooperation among companies and want strategic tie-ups in marketing field, whereas the ventures in the provinces are active in technical cooperation with university and want strategic tie-ups in technical development field. Third, ventures in the metropolitan area are more excellent in technical development and management than ventures in the provinces.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.3
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• pp.428-441
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• 2008

This article verifies the actual conditions of the Wonju area medical devices cluster for presentation of method for increasing promotion. It examines the general status of companies, reason for location, competitive power and supporting system with a questionnaire survey and in-depth research. The Wonju area has 79 medical device companies. It comprised 9% of total sales and 11% of export sales of korea medical devices in 2007. For enhancement of the Wonju area medical devices ability to accumulate and attract of medical device companies and front-line and back-line industries, the followings is needed, a supply of highly qualified man power, a support base for developing modem technology and information marketing, adequate infrastructure for housing and education system, methodologies for sustaining new business and innovation fund-raising programs and marketing, and provide the highest degree of education for CEO.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.93-98
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• 2018

This paper introduces the development of HF(NFC) and UHF band(13.56 MHz, 920 MHz) tag antennas, imbedded in a box. In dual band antennas, the HF band tag can be used to inspect the box using NFC, and the UHF band tag can be used for logistics. The dielectric constant of the box material is measured and used for simulation. The Ntag213 chip manufactured by NXP is used in HF loop antennas, since NFC is possible with Ntag213. For the UHF band, the Higgs-3 chip manufactured by Alien is used. The HF tag antenna is located at the center of the UHF tag antenna, and the location of the HF tag antenna is calculated while considering coupling effects. The designed tag can be used by both the bands for the purposes of logistics and authentication.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.785-790
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• 2020

In addition to the Fourth Industrial Revolution, interest and research on medical information are actively being conducted. As the technologies using short-range low-power wireless communication are applied in connection with mobile devices, the utilization of them in medical institutions is gradually increasing, and the demand of customers who want to receive high-quality services using IT technology is increasing in the medical environment according to the development and change of technology. In addition, modern people who are familiar with smart equipment and consider the value of time is important do not waste their time through rapid service. In addition, as the recent epidemics including Coronavirus Disease 2019 (COVID-19) have become popular, interest in untapped (non-face-to-face) has increased, and social distance is needed as a preliminary measure against infectious diseases. For this reason, this study studied the untapped-based medical reception system to provide quick service to patients using short-range low-power wireless communication and to provide safer and more comfortable environment for medical staff and visitors.

• Journal of the Korean Home Economics Association
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• v.36 no.7
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• pp.123-141
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• 1998

본 연구는 미국의 직장근무자와 재택근무자의 비교를 통해, 남성과 여성의 소득차이를 살펴보고 이를 설명하는 요소들에 대해 분석하였다. 본 연구를 위해 설정된 가설은 다음과 같다.: (1) 성별은 직업과 시장노동의 장소를 선택하는데 있어서 유의한 요소이다. (2) 직업 및 시장노동의 장소가 결정된 후에도 성별은 시간당 소득에 영향을 미치는 변수이다. 연구자료로는 Census of Population and Housing, 1990 [United States]: Public Use Microdata Sample: 1/10,000 Sample이 이용되었으며, 16세 이상, 65세 이하의 응답자로 일주일에 적어도 한 시간 이상 일하는 근로자를 중심으로 하여 7,272명이 연구 대상으로 고려되었다. 직업 및 시장노동의 장소에 대한 선택에서 성별의 영향을 살펴보기 위해 판별분석이 행해졌으며, 분석 결과 교육수준, 연령, 인종, 남녀의 수, 주택구조와 함께 성별이 유의한 요소임이 밝혀졌다. 직업과 시장노동의 장소가 결정된 후 성별이 시간당 소득에 미치는 영향을 알아보기 위해 전체표본과 6개의 직업범주에 따라 회귀분석이 실시되었다. 전체표본을 대상으로 한 회귀분석의 결과, 시간당 소득을 예측하는데 있어서 성별은 유의하지 않은 것으로 나타났으나, 6개의 직업범주에 따라 시간당 소득을 추정한 결과, 성별은 모든 직업범주에서 유의한 것으로 나타났다. 그러나 재택근무자가 되는 것은 시간당 소득을 규정하는데 있어서 유의한 변수가 아닌 것으로 나타났다. 이것은 특정 직업 내에서 시장노동의 장소보다는 성별이 재택근무자에 있어서 소득의 차이를 설명하는데 중요한 요소임을 암시하고 있다. 본 연구에서 사용된 자료는 직업 및 시장노동의 장소에 대한 결정이나 소득에 영향을 미칠 수 있는 변수들에 대한 충분한 정보를 갖고 있지 않고, 또한 재택근무자의 표본수가 너무 적었기 때문에 일부 변수들은 직업의 선택이나 소득을 예측하기 위한 요소들로 포함될 수 없었다. 따라서 후속연구에서는 이를 보완해야 할 것이며, 최근 들어 우리 나라에서도 재택근무에 대한 관심이 대두되고 있으나 아직 개념정의나 그 중요성과 가치, 그리고 실태 파악과 같은 연구가 활발히 이루어지지 못하고 있으므로 이에 대한 심층적인 연구가 행해져야 할 것이다.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.707-716
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• 2006

When the regression function is discontinuous at a point, the variance function is usually discontinuous at the point. In this case, we had better propose a test for the existence of a discontinuity point with the regression function rather than the variance function. In this paper we consider that the variance function only has a discontinuity point. We propose a nonparametric test for the existence of a discontinuity point with the second moment function since the variance function and the second moment function have the same location and jump size of the discontinuity point. The proposed method is based on the asymptotic distribution of the estimated jump size.

• Journal of the Korean Data and Information Science Society
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• v.23 no.4
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• pp.765-775
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• 2012

The cross-validation is a popular method to select bandwidth in all types of kernel estimation. The maximum likelihood cross-validation, the least squares cross-validation and biased cross-validation have been proposed for bandwidth selection in kernel density estimation. In the case that the probability density function has a discontinuity point, Huh (2012) proposed a method of bandwidth selection using the maximum likelihood cross-validation. In this paper, two forms of cross-validation with the one-sided kernel function are proposed for bandwidth selection to estimate the location and jump size of the discontinuity point of density. These methods are motivated by the least squares cross-validation and the biased cross-validation. By simulated examples, the finite sample performances of two proposed methods with the one of Huh (2012) are compared.