• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3117-3130
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• 2016

High peak-to-average power ratio (PAPR) of transmitted signals is a major drawback in Multicarrier modulation (MCM) systems. Companding transform is a well-known method to reduce the PAPR without restrictions on system parameters such as the number of subcarriers, frame format and constellation type. In this paper, a novel adaptive companding scheme, mainly focuses on compressing the large signals into the desirable distribution, is proposed to reduce the PAPR with low implementation complexity. In addition, formulas to calculate its PAPR and bit error rate (BER) performance are also derived. Simulation results confirm that the proposed scheme can achieve an effective tradeoff between PAPR reduction and BER performance by carefully choosing the companding parameter.

• 한국산업정보학회논문지
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• 제11권5호
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• pp.132-140
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• 2006

ERP 시스템 교육은 새로운 시스템에 대한 구성원들의 교육 및 연수과정에서 많은 문제점을 초래할 수도 있다. 그러한 문제점을 해결하기 위한 방안으로 시간, 장소 등에 구애받지 않고 교육을 할 수 있는 e-러닝을 활용한 ERP 교육이 대두되었다. 본 연구에서는 ERP 시스템 구축관련 조직변화관리 지원을 위한 e-러닝 활용전략으로 ERP 교육컨텐츠의 질 개선, 상호작용(피드백)의 강화, 블렌디드 러닝의 활용, ERP 시스템과 e-러닝 시스템 연계 모델 등을 제시하였다.

• 한국산업정보학회논문지
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• 제3권1호
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• pp.49-65
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• 1998

The trend toward globalization and competitive advantage is increasing the importance of international data communication . The more companies attempt to be globalized and competitive, the more critical the problems of the computer networks are. To improve computer networks in the business world, it is believed that the network shoud be approached from the viewpoint of service quality : we need to understand what network quality means to network users, those who use the network. The purpose of this study is to develop a dimension that captures the aspects of network quality that are important to network users. Many articles show that speed is very important factor in network systems. But the more important thing is that speed is just one of the factors contributing to network quality. It is suggested that a quality network meet nine dimensions : (1) speed (2) accessibility (3) connectivity (4) security (5) compatibility, (6) government restrictions (7) complexity (8) sustainability and (9) sharability.

• 한국항공운항학회지
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• 제21권1호
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• pp.15-22
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• 2013

In oceanic flight routes, HF radio and satellite data links have weather restrictions, long propagation delay and low data throughput. In this paper, we propose oceanic aeronautical communications scheme in the VHF band based on ad-hoc communication. The proposed scheme organizes autonomously a multi-hop network that is divided into multiple local network using aircraft to fly long-distance communication and supports a hybrid type of multiple access, which consists of random access and TDMA (Time Division Multiple Access) scheme. In addition, several algorithms to apply spatial reuse of transmission to multi-hop long range communication environments have been proposed. The proposed system proves performance improvement on delay time as an effective solution to communicate end-to-end on the oceanic flight routes and strengthens the reliability of oceanic aeronautical communication.

• Archives of Plastic Surgery
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• 제40권5호
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• pp.630-632
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• 2013

Vacuum-assisted wound healing has been proven to be more efficacious than conventional dressings. Vacuum dressing has been frequently modified given the restrictions in resources available. Here we present a modified method of vacuum dressing by using surgical or gynaecological gloves for lower and upper limb wounds. Vacuum dressing was applied with parts of a surgical or gynaecological glove and Opsite with T-tailing of the suction outlet. Vacuum-assisted wound healing using the surgical gloves showed relatively good wound healing in the amputation stump, finger, arm, and leg in the cases studied.

• 품질경영학회지
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• 제28권2호
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• pp.135-146
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• 2000

This study has adapted a genetic algorithm for an optimal design for the first time. The models using a simulation are the nonlinear models. Using an genetic algorithm in D-optimal, it is more efficient than previous algorithms to get an object function. Not like other algorithms, without any troublesome restrictions about the initial solution, not falling into a local optimal solution, it's the most suitable algorithm. Also if we use it without any adding experiments, we can use it to find optimal design of experimental condition efficiently.

• Journal of the Korean Statistical Society
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• 제31권1호
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• pp.63-75
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• 2002

Most attempts at Bayesian analysis of neural networks involve hierarchical modeling. We believe that similar results can be obtained with simpler models that require less computational effort, as long as appropriate restrictions are placed on parameters in order to ensure propriety of posterior distributions. In particular, we adopt a model first introduced by Lee (1999) that utilizes an improper prior for all parameters. Straightforward Gibbs sampling is possible, with the exception of the bias parameters, which are embedded in nonlinear sigmoidal functions. In addition to the problems posed by nonlinearity, direct sampling from the posterior distributions of the bias parameters is compounded due to the duplication of hidden nodes, which is a source of multimodality. In this regard, we focus on sampling from the marginal posterior distribution of the bias parameters with Markov chain Monte Carlo methods that combine traditional Metropolis sampling with a slice sampler described by Neal (1997, 2001). The methods are illustrated with data examples that are largely confined to the analysis of nonparametric regression models.

• Journal of the Korean Statistical Society
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• 제24권2호
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• pp.481-493
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• 1995

An ARIMA signal observed with measurement error is shown to have another ARIMA representation with nonlinear restrictions on parameters. For this model, the restricted Newton-Raphson estimator(RNRE) of the unit root is shown to have the same limiting distribution as the ordinary least squares estimator of the unit root in an AR(1) model tabulated by Dickey and Fuller (1979). The RNRE of parameters of the ARIMA(p,1,k) process and unit root tests base on the RNRE are developed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.388-393
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• 1997

As the aircraft noise become the serious matter nowadays, registrations controlling the noise emission from aircraft are established to set up noise protection areas such as residential buildings and schools. Several methods are used to assess the noise impact of an airport on its surroundings. WECPNL is used as the aircraft legislation noise index in Korea and in Japan. In this paper, experiments were made to assess the total noise impact of Kwangju airport area by using WECPNL. Also restrictions related to buildings in this area and grants were reviewed to improve building attention in the inner zone.

• 한국언어정보학회지:언어와정보
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• 제5권1호
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• pp.35-53
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• 2001

As a subtype of English relative clause constructions, free relative constructions like what John ate in I ate what John ate exhibit complicated syntactic and semantic properties. In particular, the constructions have mixed properties of nominal and verbal: they have the internal syntax of sentence and the external syntax of noun phrase. This paper provides a constraint-based approach to these mixed constructions, and shows that simple constructional constraints are enough to capture their complexities. The paper begins by surveying the properties of the constructions. In discusses two types(Specific and nonspecific) of free relatives, their ,lexical restrictions nominal properties and behavior with respect to extraposition, piped piping and stacking Following these it sketches the basic framework of the HPSG(Head-driven Phrase Structure Grammar) which is of relevance in this paper. As the main part, the paper presents a constraint- based analysis in which tight interactions between grammatical constructions and a rich network of inheritance relations play important roles in accounting for the basic as well as complex properties of the constructions is question.