• 한국전자통신학회논문지
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• 제13권4호
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• pp.881-886
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• 2018

지난 수십 년간, 컴퓨터 기술의 발전은 응용연구의 데이터집약형 연구라는 새로운 패러다임으로 변화를 가져왔다. 지리적으로 떨어진 연구자들에게 대용량 실험 데이터를 저장, 공유, 분석하는 환경이 요구되고, 우리나라는 연구 경쟁력 강화를 위해 국가과학기술연구망(KREONET)과 대용량데이터센터 등 국가 차원의 인프라를 서비스하고 있다. 특히, KREONET는 2016년부터 세계 주요 연구지까지 최대 100Gbps의 속도로 연결하는 네트워크를 제공하고 있다. 본 논문에서는 국제간 협업을 지원하는 초고속 장거리 전송의 연구 환경으로서, 고성능 전송 노드와 계산 자원을 고속의 네트워크에 연동한 대용량 데이터전용의 전송플랫폼 시연 결과를 소개하고자 한다.

• 한국항만경제학회지
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• 제18권2호
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• pp.27-45
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• 2002

The continuing pace of technological change and the trend toward larger and faster ships is evident as shipping lines compete in seeking economies of scale in the global market and ports. become increasingly reliant on sophisticated equipment. Across the Asia and Pacific region some of the worlds most modern container ships are calling at an extensive network of mainline and feeder ports. This paper shows that during the period from 1999 to 2011, Asian container trade is expected to continue to increase more rapidly than the world average, i.e., 7.2 per cent per annum compared with the world average of 6.3 per cent. It is forecast that the total volumes of international containers handled at the ports in Asia and the Pacific will increase at an average growth rate of 7,2 per cent per annum. In order to handle the anticipated port container traffic in 2011, new container berths are required in nearly every country in the Asia and the Pacific region. This will entail very significant capital investment requirements. If countries in the UNESCAP region are to position their ports to meet the challenges of the next decade, there is an urgent need to implement more robust strategies to address important issues including prioritisation of port development projects, promotion of private sector participation in ports, emphasis on productivity and preparation for intermodal integration and logistics growth.

• 한국항해항만학회지
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• 제45권2호
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• pp.75-86
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• 2021

This paper intends to evaluate the policies which are considered necessary to enhance the T/S competitiveness of Busan's port, and thereby present suggestions to the government which would best implement the results of this research. This research first raises the claim that the majority of the following four conditions: location of the port, port productivity/service level, status of network with overseas ports, and cost competitiveness, should be satisfied in order to maintain a competitive T/S port. Based on these four conditions, seven policies, which are individually pertinent to the four conditions, have been drawn up for proposal, and they are also analyzed in the survey, where all the eligible samples participate to ensure if they are effective in enhancing the T/S competitiveness of Busan. Proposed important policies are a) Terminal operator integration, b) port infrastructure expansion, c) global carriers owned terminal operation, d) enhancement of national carrier's competitiveness, e) feeder carriers' owned terminal operation in new port, f) institutional support for effective and convenient environments for handling T/S cargo, and g) volume incentive expansion. From the analysis by which all the relevant parties (Carriers, Terminal Operators, Port Authority) are answered, it was found that all the seven policies have relevance in strengthening the transshipment competitiveness of Busan's port. Whereas in the analysis that uses AHP methodology to compare the significance among the different policies, it was found that terminal operator integration has the highest priority in terms of increasing transshipment competitiveness.

• Steel and Composite Structures
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• 제44권4호
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• pp.587-602
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• 2022

In this study, the classical J₂ flow theory is explicitly proved to be inappropriate to describe the plastic behaviour of structural steels under different stress states according to the reported test results. A numerical framework of the characterization of the strain hardening and ductile fracture initiation involving the effect of stress states, i.e., stress triaxiality and Lode angle parameter, is proposed based on the mechanical response of structural steels under monotonic loading. Both effects on strain hardening are determined by correction functions, which are implemented as different modules in the numerical framework. Thus, other users can easily modify them according to their test results. Besides, the ductile fracture initiation is determined by a fracture locus in the space of stress triaxiality, Lode angle parameter, and fracture strain. The numerical implementation of the proposed model and the corresponding code are provided in this paper, which are also available on GitHub. The validity of the numerical procedure is examined through single element tests and the accuracy of the proposed model is verified by existing test results.

• 한국전자거래학회지
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• 제21권3호
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• pp.79-99
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• 2016

본 연구는 실시간으로 생성되는 전자세금계산서(e-invoice) 데이터를 활용하여 자동차 부품산업 내의 공급망을 분석하였다. 완성차에게 부품을 공급하는 모듈단위 업체를 1차 업체라고 정의하였으며 총 8가지 모듈 단위 중에서 제동장치의 서브 모듈인 브레이크를 중심으로 2차/3차 공급망 분석을 실시하였다. 2차 브레이크 생산 업체는 3개 업체로, 이들 업체의 에고 네트워크 분석을 토대로 각 업체의 3차 하청업체들의 네트워크상에서의 역할-통합자와 할당자 그리고 허브- 규명되었다. 네트워크 수준 분석에서는 브레이크 업계 점유율 1위인 $A_2$의 네트워크는 다른 2개의 경쟁 업체보다 업체 수가 많고 권한이 집중되어 있는 것으로 나타났다. 또한 브레이크업계 사업유형별 거래 전 속도를 통해 거래적 위상관계를 분석하였는데 전체 업체의 37%가 위계적 거래였으며 사업유형 관점에서 도매업, 상품중개업 그리고 고무 제품 및 플라스틱 제품제조업의 거래 전속도 값이 1일 정도로 위계적 거래관계인 사실을 입증했다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권4호
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• pp.1224-1248
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• 2022

In various sensor network applications, such as climate observation organizations, sensor nodes need to collect information from time to time and pass it on to the recipient of information through multiple bounces. According to field tests, this information corresponds to most of the energy use of the sensor hub. Decreasing the measurement of information transmission in sensor networks becomes an important issue.Compression sensing (CS) can reduce the amount of information delivered to the network and reduce traffic load. However, the total number of classification of information delivered using pure CS is still enormous. The hybrid technique for utilizing CS was proposed to diminish the quantity of transmissions in sensor networks.Further the energy productivity is a test task for the sensor nodes. However, in previous studies, a clustering approach using hybrid CS for a sensor network and an explanatory model was used to investigate the relationship between beam size and number of transmissions of hybrid CS technology. It uses efficient data integration techniques for large networks, but leads to clone attacks or attacks. Here, a new algorithm called SBEA (Snowball Endurance Algorithm) was proposed and tested with a bow. Thus, you can extend the battery life of your WSN by running effective copy detection. Often, multiple nodes, called observers, are selected to verify the reliability of the nodes within the network. Personal data from the source centre (e.g. personality and geographical data) is provided to the observer at the optional witness stage. The trust and reputation system is used to find the reliability of data aggregation across the cluster head and cluster nodes. It is also possible to obtain a mechanism to perform sleep and standby procedures to improve the life of the sensor node. The sniffers have been implemented to monitor the energy of the sensor nodes periodically in the sink. The proposed algorithm SBEA (Snowball Endurance Algorithm) is a combination of ERCD protocol and a combined mobility and routing algorithm that can identify the cluster head and adjacent cluster head nodes.This algorithm is used to yield the network life time and the performance of the sensor nodes can be increased.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.24-31
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• 2020

기존의 컴퓨팅 환경에서 사용되는 중앙 집중형 시스템은 해킹에 의한 개인정보 침해 사례와 시스템 장애 발생시 가용성 침해 문제 등의 다양한 문제점을 가지고 있다. 현재 신뢰받는 차세대 융합 정보 핵심 기술 중 하나인 블록체인은 다양한 문제점을 가지고 있던 기존의 중앙 집중형 시스템의 대안 기술로 기대 되고 있으며, 블록체인 환경에 맞는 사용자 인증 시스템의 필요성이 증가 하고 있다. 본 논문은 온라인 환경에서 EID를 이용하여 사용자 식별이 가능한 블록체인 기반의 사용자 통합 인증 시스템을 제안한다. 기존 ID/PW 인증 방식은 사용자가 여러 사이트에 개인정보를 저장하고 각각의 ID를 발급 받아 사용해야 한다. 그러나 제안하는 시스템은 EID 발급 후 여러 사이트에서 회원가입 없이 사용이 가능하다. 제안 시스템은 이메일 및 전화번호 등 최소한의 정보로 EID를 발급한다. 기존 중앙 집중형 시스템과 제안하는 통합 인증 시스템의 안정성과 효율성을 비교하여 우수함을 입증하였다. 컴퓨팅 환경에서 발생하는 공격방법과 침해 요소를 선택하여 기존 시스템과의 안정성을 비교 하였다. 또한 효율성의 검증을 위하여 인증과정에서 발생하는 사용자의 App, 발행 및 인증기관의 서버, 서비스 제공기관 서버 사이의 총 처리량을 트랜잭션 당 처리시간으로 비교 분석하였다.

• 정보처리학회 논문지
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• 제13권6호
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• pp.284-290
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• 2024

음성감정인식(Speech Emotion Recognition, SER)은 사용자의 목소리에서 나타나는 떨림, 어조, 크기 등의 음성 패턴 분석을 통하여 감정 상태를 판단하는 기술이다. 하지만, 기존의 음성 감정인식 연구는 구현된 시나리오를 이용하여 제한된 환경 내에서 숙련된 연기자를 대상으로 기록된 음성인 구현발화를 중심의 연구로 그 결과 또한 높은 성능을 얻을 수 있지만, 이에 반해 자유발화 감정인식은 일상생활에서 통제되지 않는 환경에서 이루어지기 때문에 기존 구현발화보다 현저히 낮은 성능을 보여주고 있다. 본 논문에서는 일상적 자유발화 음성을 활용하여 감정인식을 진행하고, 그 성능을 향상하고자 한다. 성능평가를 위하여 AI Hub에서 제공되는 한국인 자유발화 대화 음성데이터를 사용하였으며, 딥러닝 학습을 위하여 1차원의 음성신호를 시간-주파수가 포함된 2차원의 스펙트로그램(Spectrogram)로 이미지 변환을 진행하였다. 생성된 이미지는 CNN기반 전이학습 신경망 모델인 VGG (Visual Geometry Group) 로 학습하였고, 그 결과 7개 감정(기쁨, 사랑스러움, 화남, 두려움, 슬픔, 중립, 놀람)에 대해서 성인 83.5%, 청소년 73.0%의 감정인식 성능을 확인하였다. 본 연구를 통하여, 기존의 구현발화기반 감정인식 성능과 비교하면, 낮은 성능이지만, 자유발화 감정표현에 대한 정량화할 수 있는 음성적 특징을 규정하기 어려움에도 불구하고, 일상생활에서 이루어진 대화를 기반으로 감정인식을 진행한 점에서 의의를 두고자 한다.

• 한국전자거래학회지
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• 제26권1호
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• pp.43-65
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• 2021

정보통신기술의 발달에 따라 IT 인력 채용 방식에도 많은 변화가 생겼다. 채용 담당자들은 이력서나 면접과 같은 전통적인 정보 이외에도 웹에서 구직자 정보를 검색할 수 있다. 오픈소스 소프트웨어 개발(OSSD) 플랫폼은 개발자들이 자연스럽게 IT 역량을 발휘할 수 있는 곳이자, 채용 담당자들이 적합한 후보를 찾을 수 있는 장소가 되었다. 이러한 맥락에서 본 연구는 취업 시 OSSD 플랫폼의 개발자 정보(구직 활동 여부, 개인정보 게시 정도, 학습 활동 정도, 지식공헌 활동 정도)가 취업에 미치는 영향을 분석하였다. 실증분석을 위해 웹 크롤러를 개발하여 대표적인 OSSD 플랫폼인 깃허브의 개발자 4,005명을 대상으로 데이터를 수집했다. 구직 기간이 짧다는 것은 취업의 성공적인 결과를 의미하기 때문에 구직 기간에 영향을 미치는 요인을 살펴보기 위해 생존분석법을 실시하였다. 본 연구의 결과에 따르면, 구직 현황을 명시적으로 게시한 개발자가 그렇지 않은 개발자보다 구직 기간이 짧은 것으로 나타났다. 개인정보 게시 정도, 학습 활동 및 지식공헌 활동 정도 또한 구직기간 단축과 긍정적으로 관련이 있는 것으로 나타났다. 본 연구는 향후 채용 담당자의 성공적인 구인뿐만 아니라 개발자의 효과적인 구직을 위한 OSSD 플랫폼의 전략적인 활용 방안에 시사점을 제시해줄 것이다.

• Asia pacific journal of information systems
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• 제17권4호
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• pp.31-59
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• 2007

We frequently use search engines to find relevant information in the Web but still end up with too much information. In order to solve this problem of information overload, ranking algorithms have been applied to various domains. As more information will be available in the future, effectively and efficiently ranking search results will become more critical. In this paper, we propose a ranking algorithm for the Semantic Web resources, specifically RDF resources. Traditionally, the importance of a particular Web page is estimated based on the number of key words found in the page, which is subject to manipulation. In contrast, link analysis methods such as Google's PageRank capitalize on the information which is inherent in the link structure of the Web graph. PageRank considers a certain page highly important if it is referred to by many other pages. The degree of the importance also increases if the importance of the referring pages is high. Kleinberg's algorithm is another link-structure based ranking algorithm for Web pages. Unlike PageRank, Kleinberg's algorithm utilizes two kinds of scores: the authority score and the hub score. If a page has a high authority score, it is an authority on a given topic and many pages refer to it. A page with a high hub score links to many authoritative pages. As mentioned above, the link-structure based ranking method has been playing an essential role in World Wide Web(WWW), and nowadays, many people recognize the effectiveness and efficiency of it. On the other hand, as Resource Description Framework(RDF) data model forms the foundation of the Semantic Web, any information in the Semantic Web can be expressed with RDF graph, making the ranking algorithm for RDF knowledge bases greatly important. The RDF graph consists of nodes and directional links similar to the Web graph. As a result, the link-structure based ranking method seems to be highly applicable to ranking the Semantic Web resources. However, the information space of the Semantic Web is more complex than that of WWW. For instance, WWW can be considered as one huge class, i.e., a collection of Web pages, which has only a recursive property, i.e., a 'refers to' property corresponding to the hyperlinks. However, the Semantic Web encompasses various kinds of classes and properties, and consequently, ranking methods used in WWW should be modified to reflect the complexity of the information space in the Semantic Web. Previous research addressed the ranking problem of query results retrieved from RDF knowledge bases. Mukherjea and Bamba modified Kleinberg's algorithm in order to apply their algorithm to rank the Semantic Web resources. They defined the objectivity score and the subjectivity score of a resource, which correspond to the authority score and the hub score of Kleinberg's, respectively. They concentrated on the diversity of properties and introduced property weights to control the influence of a resource on another resource depending on the characteristic of the property linking the two resources. A node with a high objectivity score becomes the object of many RDF triples, and a node with a high subjectivity score becomes the subject of many RDF triples. They developed several kinds of Semantic Web systems in order to validate their technique and showed some experimental results verifying the applicability of their method to the Semantic Web. Despite their efforts, however, there remained some limitations which they reported in their paper. First, their algorithm is useful only when a Semantic Web system represents most of the knowledge pertaining to a certain domain. In other words, the ratio of links to nodes should be high, or overall resources should be described in detail, to a certain degree for their algorithm to properly work. Second, a Tightly-Knit Community(TKC) effect, the phenomenon that pages which are less important but yet densely connected have higher scores than the ones that are more important but sparsely connected, remains as problematic. Third, a resource may have a high score, not because it is actually important, but simply because it is very common and as a consequence it has many links pointing to it. In this paper, we examine such ranking problems from a novel perspective and propose a new algorithm which can solve the problems under the previous studies. Our proposed method is based on a class-oriented approach. In contrast to the predicate-oriented approach entertained by the previous research, a user, under our approach, determines the weights of a property by comparing its relative significance to the other properties when evaluating the importance of resources in a specific class. This approach stems from the idea that most queries are supposed to find resources belonging to the same class in the Semantic Web, which consists of many heterogeneous classes in RDF Schema. This approach closely reflects the way that people, in the real world, evaluate something, and will turn out to be superior to the predicate-oriented approach for the Semantic Web. Our proposed algorithm can resolve the TKC(Tightly Knit Community) effect, and further can shed lights on other limitations posed by the previous research. In addition, we propose two ways to incorporate data-type properties which have not been employed even in the case when they have some significance on the resource importance. We designed an experiment to show the effectiveness of our proposed algorithm and the validity of ranking results, which was not tried ever in previous research. We also conducted a comprehensive mathematical analysis, which was overlooked in previous research. The mathematical analysis enabled us to simplify the calculation procedure. Finally, we summarize our experimental results and discuss further research issues.