• Progress in Medical Physics
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• v.5 no.1
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• pp.55-66
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• 1994

After proving home-made imaging pulse sequences including tailored RF pulse by phantom, susceptibility-contrast-enhanced MR venograms of cat brain were obtained using tailored RF gradient-echo(TRGE) method. Sagittal MR imaging of the cat brain obtained by TRGE technique shows several veins, for example, dorsal sagittal sinus, straight sinus, vein of corpus callosum and internal cerebral vein, etc., compared with cats anatomical figure. Tailored RF waveform was generated by PASCAL language in ASPECT 3000 computer(Switzland, Bruker). Rectangular-shaped slice profile with bi-linear ramp function as phase distribution in the slice, at which maximum value was 2$\pi$, was fourier transformed to make tailored RF pulse. Experimental MR imaging parameters were TR/TE=205/10 msec, slice thickness TH=7mm, maxtrix size=256$\times$256, in-plane resolution=0.62$\times$0.31mm$^2$, and field of view(FOV)=8cm for both conventional gradient-echo(GE) imaging and TRGE imaging techniques.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.37-52
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• 2011

Supply chain management is a strategic thinking which enhances the value of supply chain and adapts more promptly for the changing environment. For the seamless partnership and value creation in supply chains, information and knowledge sharing and proper partner selection criteria must be applied. Thus, the partner selection criteria are critical to maintain product quality and reliability. Each part of a product is supplied by an appropriate supply partner. The criteria for selecting partners are technological capability, quality, price, consistency, etc. In reality, the criteria for partner selection may change according to the characteristics of the components. When the part is a core component, quality factor is the top priority compared to the price. For a standardized component, lower price has a higher priority. Sometimes, unexpected case occurs such as emergency order in which the preference may shift on the top. Thus, SCM partner selection criteria must be determined dynamically according to the characteristics of part and its context. The purpose of this research is to develop an OWL model for the supply chain partnership depending on its context and characteristics of the parts. The uncertainty of variable is tackled through fuzzy logic. The parts with preference of numerical value and context are represented using OWL. Part preference is converted into fuzzy membership function using fuzzy logic. For the ontology reasoning, SWRL (Semantic Web Rule Language) is applied. For the implementation of proposed model, starter motor of an automobile is adopted. After the fuzzy ontology is constructed, the process of selecting preference-based supply partner for each part is presented.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.122-133
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• 1999

Uses can share information and use resources effectively by using TCP/IP-based networks. So, a protocol to manage complex networks effectively is needed. For the management of the distributed networks, the SNMP(Simple Network Management Protocol) has been adopted as an international standard in 1989, and the SNMPv2 in which a security function was added was published in 1993. There are two encryption schemes in SNMPv2, the one is a DES using symmetric encryption scheme and the other is a MD5(Message Digest5) hash function for authentication. But the DES has demerits that a key length is a few short and the encryption and the authentication is executed respectively. In order to solve these problems, wer use a RSA cryptography in this paper. In this paper, we examine the items related with SNMP. In addition to DES and MD5 propose in SNMPv3, we chance security functionality by adopting RSA, a public key algorithm executing the encryption and the authentication simultaneously. The proposed SNMPv3 security module is written in JAVA under Windows NT environment.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.9
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• pp.377-384
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• 2017

The performance improvement of a single core processor has reached its limit since the circuit density cannot be increased any longer due to overheating. Therefore, the multicore and manycore architectures have emerged as viable approaches and parallel programming becomes more important. Haskell, a purely functional language, is getting popular in this situation since it naturally supports parallel programming owing to its beneficial features including the implicit parallelism in evaluating expressions and the monadic tools supporting parallel constructs. However, the performance of Haskell parallel programs is strongly influenced by the performance of the run-time system including the garbage collector. Though a memory profiling tool namely GC-tune has been suggested, we need a more systematic way to use this tool. Since GC-tune finds the optimal memory size by executing the target program with all the different possible GC options, the GC-tuning time takes too long. This paper suggests a basic divide-and-conquer method to reduce the number of GC-tune executions by reducing the search area by one-quarter for every searching step. Applying this method to two parallel programs, a maximally independent set and a K-means programs, the memory tuning time is reduced by 7.78 times with accuracy 98% on average.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.11
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• pp.64-74
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• 1999

A new clock skew optimization for clock routing using link-edge insertion is proposed in this paper. It satisfies the given skew bound and prevent the total wire length from increasing. As the clock skew is the major constraint for high speed synchronous ICs, it must be minimized in order to obtain high performance. But clock skew minimization can increase total wire length, therefore clock routing is performed within the given skew bound which can not induce the malfunction. Clock routing under the specified skew bound can decrease total wire length Not only total wire length and delay time minimization algorithm using merging point relocation method but also clock skew reduction algorithm using link-edge insertion technique between two nodes whose delay difference is large is proposed. The proposed algorithm construct a new clock routing topology which is generalized graph model while previous methods uses only tree-structured routing topology. A new cost function is designed in order to select two nodes which constitute link-edge. Using this cost function, delay difference or clock skew is reduced by connecting two nodes whose delay difference is large and distance difference is short. Furthermore, routing topology construction and wire sizing algorithm is developed to reduce clock delay. The proposed algorithm is implemented in C programming language. From the experimental results, we can get the delay reduction under the given skew bound.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.19-31
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• 2013

Since the high readable source codes help us to understand and modify the program, it is much easy to maintain them. The readability of source code is not only affected by the complexity of algorithms such as control structures but also affected by the coding styles such as naming and indentation. Although various coding standards have been presented for promoting the readability of source codes, it has been usually lost or ignored in a programming course. One of the reasons is that the coding standard is not a hard-and-false rule since it does not contribute to the performance of software. In this paper, we propose a simple automatic system, namely StyleJigsaw, which checks the style of the source codes written by C/C++ or Java. In this system, the coding style score is calculated and visualized as a jigsaw puzzle. To measure the educational effectiveness of StyleJigsaw, several experiments have been conducted on a class students in C++ programming course. According to the experimental results, the coding style score increased about 8.0 points(10.9%) on average using StyleJigsaw. Further, according to a questionnaire survey targeting the students who attended the programming course, about 88.5% of the students responded that StyleJigsaw was of help to learn the coding standards. We expect that the StyleJigsaw can be effectively used to encourage the students to obey the coding standards, resulting in high readable programs.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.607-614
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• 2014

This article aims to explore and discuss research trends in global cruise industry using keyword network analysis. We visualize keyword networks in each of four groups of 1982-1999, 2000-2004, 2005-2009, 2010-2014 based on the top 20 keyword nodes' degree centrality and betweenness centrality which are selected among four centrality measurements, comparing them with frequency order. The article shows that keyword frequency collected from 240 articles published in international journals is subject to Zipf's law and nodes degree distribution also exhibits power law. We try to find out research trends in global cruise industry to change some important keywords diachronically, visualizing several networks focusing on the top two keywords, cruise and tourism, belonging to all the four year groups, with high degree and betweenness centrality values. Interestingly enough, a new node, China, connecting the top most keywords, appears in the most recent period of 2010-2014 when China has emerged as one of the rapid development countries in global cruise industry. Therefore keyword network analysis used in this article will be useful to understand research trends in global cruise industry because of increase and decrease of numbers of network types in different year groups and the visual connection between important nodes in giant components.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.4
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• pp.137-144
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• 2020

Delirium is among the most common mental disorders encountered in patients with a temporary cognitive impairment such as consciousness disorder, attention disorder, and poor speech, particularly among those who are older. Delirium is distressing for patients and families, can interfere with the management of symptoms such as pain, and is associated with increased elderly mortality. The purpose of this paper is to generate useful clinical knowledge that can be used to distinguish the outcomes of patients with delirium in long-term care facilities. For this purpose, we extracted the clinical classification knowledge associated with delirium using a local covering rule acquisition approach with the rough lower approximation region. The clinical applicability of the proposed method was verified using data collected from a prospective cohort study. From the results of this study, we found six useful clinical pieces of evidence that the duration of delirium could more than 12 days. Also, we confirmed eight factors such as BMI, Charlson Comorbidity Index, hospitalization path, nutrition deficiency, infection, sleep disturbance, bed scores, and diaper use are important in distinguishing the outcomes of delirium patients. The classification performance of the proposed method was verified by comparison with three benchmarking models, ANN, SVM with RBF kernel, and Random Forest, using a statistical five-fold cross-validation method. The proposed method showed an improved average performance of 0.6% and 2.7% in both accuracy and AUC criteria when compared with the SVM model with the highest classification performance of the three models respectively.

• Communications of Mathematical Education
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• v.29 no.4
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• pp.573-588
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• 2015

In this paper, we introduce development process and application of a simple and effective model of a statistics laboratory using open source software R, one of leading language and environment for statistical computing and graphics. This model consists of HTML files, including Sage cells, video lectures and enough internet resources. Users do not have to install statistical softwares to run their code. Clicking 'evaluate' button in the web page displays the result that is calculated through cloud-computing environment. Hence, with any type of mobile equipment and internet, learners can freely practice statistical concepts and theorems via various examples with sample R (or Sage) codes which were given, while instructors can easily design and modify it for his/her lectures, only gathering many existing resources and editing HTML file. This will be a resonable model of laboratory for studying statistics. This model with bunch of provided materials will reduce the time and effort needed for R-beginners to be acquainted with and understand R language and also stimulate beginners' interest in statistics. We introduce this interactive statistical laboratory as an useful model for beginners to learn basic statistical concepts and R.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.253-257
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• 2007

최근 웹 상에 정보가 폭발적으로 증가함에 따라, 사용자의 취향에 맞는 정보를 선별하여 제공하는 추천 시스템에 대한 연구가 활발히 진행되고 있다. 추천시스템은 사용자의 관심정보를 기술한 사용자 프로파일을 기반으로 동작하기 때문에 정확한 사용자 프로파일의 생성은 매우 중요하다. 사용자의 암시적인 행동정보를 기반으로 취향을 분석하는 대표적인 연구로 사용자가 이용한 웹 문서를 분석하는 방법이 있다. 이는 사용자가 이용하는 웹 문서에 빈번하게 등장하는 단어를 기반으로 사용자의 프로파일을 생성하는 것이다. 그러나 최근 웹 문서는 사용자 취향과 관련 없는 많은 구성요소들(로고, 저작권정보 등)을 포함하고 있다. 따라서 이러한 내용들을 모두 포함하여 웹 문서를 분석한다면 생성되는 프로파일의 정확도는 낮아질 것이다. 따라서 본 논문에서는 사용자 기기에서 사용자의 웹 문서 이용내역을 분석하고, 동일한 사이트로부터 얻어진 문서들에서 반복적으로 등장하는 블록을 제거한 후, 정보블럭을 식별하여 사용자의 관심단어를 추출하는 새로운 프로파일 생성방법을 제안한다. 이를 통해 보다 정확하고 빠른 프로파일 생성이 가능해진다. 본 논문에서는 제안방법의 평가를 위해, 최근 구매활동이 있었던 사용자들이 이용한 웹 문서 데이터를 수집하였으며, TF-IDF 방법과 제안방법을 이용하여 사용자 프로파일을 각각 추출하였다. 그리고 생성된 사용자 프로파일과 구매데이터와의 연관성을 비교하였으며, 보다 정확한 프로파일이 추출되는 결과와 프로파일 분석시간이 단축되는 결과를 통해 제안방법의 유효성을 입증하였다.)으로 높은 점수를 보였으며 내장첨가량에 따른 관능특성에서는 온쌀죽은 내장 $2{\sim}5%$ 첨가, 반쌀죽은 내장 $3{\sim}5%$ 첨가구에서 유의적(p<0.05)으로 높은 점수를 보였으나 쌀가루죽은 내장 $1{\sim}2%$ 첨가구에서 유의적(p<0.05)으로 낮은 점수를 보였다. 이상의 연구 결과를 통해 온쌀은 2%, 반쌀은 3%, 쌀가루는 4%의 내장을 첨가하여 제조한 전복죽이 이화학적, 물성적 및 관능적으로 우수한 것으로 나타났다.n)방법의 결과와 비교하였다.다. 유비스크립트에서는 모바일 코드의 개념을 통해서 앞서 언급한 유비쿼터스 컴퓨팅 환경에서의 문제점을 해결하고자 하였다. 모바일 코드에서는 프로그램 코드가 네트워크를 통해서 컴퓨터를 이동하면서 수행되는 개념인데, 이는 물리적으로 떨어져있으면서 네트워크로 연결되어 있는 다양한 컴퓨팅 장치가 서로 연동하기 위한 모델에 가장 적합하다. 이는 기본적으로 배포(deploy)라는 단계가 필요 없게 되고, 새로운 버전의 프로그램이 작성될지라도 런타임에 코드가 직접 이동하게 되므로 버전 관리의 문제도 해결된다. 게다가 원격 함수를 매번 호출하지 않고 한번 이동된 코드가 원격지에서 모두 수행을 하게 되므로 성능향상에도 도움이 된다. 장소 객체(Place Object)와 원격 스코프(Remote Scope)는 앞서 설명한 특징을 직접적으로 지원하는 언어 요소이다. 장소 객체는 모바일 코드가 이동해서 수행될 계산 환경(computational environment