• Annual Conference of KIPS
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• 2014.11a
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• pp.1096-1099
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• 2014

스마트폰의 보급률에 맞물려 스마트폰 사용으로 인한 보행자 교통사고가 증가함에 따라 전세계적으로 이에 관한 연구 또한 꾸준히 증가 추세임에도 불구하고 인구대비 스마트폰 보급률이 세계 최고인 국내에서는 이에 대한 연구가 아직 미흡한 실정이다. 본 연구에서는 보행 중 교통사고 중에서 큰 비중을 차지하고 있는 젊은층의 산만 보행에 관해 알아보고자 하였다. 본 연구는 정신과학 분야의 주의 네트워크 연구를 바탕으로 보행자의 안전도 향상은 물론, 스마트폰 이용자의 사용성을 고려한 depth-based alarming 서비스를 제안한다.-본 연구는 스마트폰 애플리케이션을 제작하여 국내 20대 스마트폰 이용자를 대상으로 피험자내 설계로 진행되었고, 보행자의 안전도에 관련한 무선조종 자동차에 대한 반응속도와 충돌여부를 측정하였고, 또한 앱 사용성에 관련한 방해도 및 만족도를 설문을 통해 측정하였다. 본 연구는 위험 상황을 알리는 alarm 을 제공하기 전에 미리 pre-alarm 을 제공하는 depth-based alarming 을 디자인 하였다. 본 연구는 실험을 통해 pre-alarm 제공시 alarm 에 대한 보행자의 반응 속도가 1.446 초 향상됨을 통계적 유의성을 통해 입증함으로써 pre-alarm 을 제공하는 depth-based alarming 서비스의 필요성을 제시한다.

• Journal of Korean Society for Quality Management
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• v.44 no.1
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• pp.29-42
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• 2016

Purpose: This paper reviews the papers on reliability issues which are published in the Journal of the Korean Society for Quality Management (KSQM) since 1965. The literature review is purposed to survey a variety of reliability issues for several categories Methods: We divide all of reliability issues into 9 categories: acceleration test, reliability estimation, system reliability, software reliability, reliability data collection and analysis method, lifetime distribution, maintenance and warranty strategy, reliability applications, and reliability applications to military area Results: Dividing all of papers on reliability published in KSQM for 50 years into 9 categories, we provide a chronological roadmap for individual categories, and summarize the contents and contributions of surveyed papers Conclusion: The review paper is expected to provide future direction to improve reliaiblity theories and applications in manufacturing and service industries

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.133-141
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• 2016

Recent web services provide tagging function to users, and let them express the topic of the contents of their articles. Moreover, we can extract context information like emotion of the writer efficiently by using tags attached to the articles or images. And we are able to better understand article than traditional algorithm. (eg. TF-IDF) Therefore, if we use tags in recommendation system, we can recommend high quality resources to the users. This study proposes a recommendation method that provide web resources (articles, users) through simple algorithm based on related tag set extracted from the article. Through the experiments, we show that the result was satisfactory, and we measure the satisfaction of users.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.35-41
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• 2015

SDN(Software Defined Networking) has been considered as a new future computer network architecture and DDoS(Distributed Denial of Service) is the biggest threat in the network security. In SDN architecture, we present the technique to defend the DDoS SYN Flooding attack that is one of the DDoS attack method. First, we monitor the Backlog queue in order to reduce the unnecessary monitoring resources. If the Backlog queue of the certain server is occupied over 70%, the sFlow performs packet sampling with the server address as the destination address. To distinguish between the attacker and the normal user, we use the source address. We decide the SYN packet threshold using the remaining Backlog queue that possible to allow the number of connections. If certain sources address send the SYN packet over the threshold, we judge that this address is attacker. The controller will modify the flow table entry to block attack traffics. By using this method, we reduce the resource consumption about the unnecessary monitoring and the protection range is expanded to all switches. The result achieved from our experiment show that we can prevent the SYN Flooding attack before the Backlog queue is fully occupied.

• Annual Conference of KIPS
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• 2015.10a
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• pp.387-389
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• 2015

IEEE 802.11e EDCA(Enhanced Distributed Channel Access)는 4개의 AC(Access Category)를 이용하여 트래픽에 따른 우선순위를 부여하고 QoS(Quality of Service)를 제공하기 위해 표준화되었다. EDCA는 이진 백오프 알고리즘을 갖는 CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) 방법을 이용한다. EDCA에서 패킷 전송에 실패할 경우 경쟁 윈도우 값은 두 배씩 증가 되고, 성공할 경우에는 최소 경쟁 윈도우 값으로 초기화된다. 따라서 경쟁 윈도우 값이 최적의 값을 유지하지 못해 많은 패킷 충돌을 야기하여 네트워크 성능을 감소시킨다. 이 문제를 해결하기 위해 기존에 제안된 논문에서는 패킷 전송 성공 후 경쟁 윈도우 값을 최소 경쟁 윈도우 값이 아닌 채널 혼잡 정도에 따라 계산된 값으로 설정한다. 그러나 이 방법은 트래픽 종류와 상관없이 같은 방법으로 동작하기 때문에 트래픽 종류에 따른 차별적 QoS를 보장하지 않는다. 또한 계산된 경쟁 윈도우 값은 현재 값에 비해 상대적으로 낮은 값을 갖기 때문에 여전히 높은 충돌율을 갖는다. 본 논문에서는 이 문제를 해결하기 위해 새로운 프로토콜을 제안한다. 제안된 방법에서는 네트워크의 혼잡 정도를 잘 반영하기 위한 새로운 경쟁 윈도우 계산 알고리즘을 제시한다. 또한 제안된 알고리즘은 트래픽 종류에 따른 QoS 보장을 위해 트래픽 종류에 따른 차별화 파라미터를 이용한다.

• Steel and Composite Structures
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• v.35 no.2
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• pp.279-294
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• 2020

Foundation of a building is damaged under service loads during construction. First visit shows that the foundation has been punched at the 6 column's foot region led to building rotation. Foundation shear punching occurring has made some stresses and deflections in construction. In this study, progressing of damage caused by foundation shear punching and inverse loading in order to resolve the building rotation has been evaluated in the foundation and frame of building by finite element modeling in ABAQUS software. The stress values of bars in punched regions of foundation has been deeply exceeded from steel yielding strength and experienced large displacement based on software's results. On the other hand, the values of created stresses in the frame are not too big to make serious damage. In the beams and columns of ground floor, some partial cracks has been occurred and in other floors, the values of stresses are in the elastic zone of materials. Finally, by inverse loading to the frame, the horizontal displacement of floors has been resolved and the values of stresses in frame has been significantly reduced.

• Annual Conference of KIPS
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• 2012.11a
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• pp.853-856
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• 2012

모바일 디바이스의 대중화와 SNS(Social Networking Service)의 발전은 각 개인이 데이터와 정보를 생성하는 Web 2.0 의 페러다임을 앞당겼으며 최근 SNS 서비스를 통하여 새로운 형태의 커뮤니케이션 형태가 생성되었다. 이러한 커뮤니케이션 도구를 이용하는 유저는 대부분 ID 와 Password를 기반으로 사용자를 인증하여 서비스를 제공받는다. 이와 같은 서비스에서는 각 사용자의 정보자체보다 사용자의 사회적 위치와 사용자간의 관계를 이용한 보안사고가 우려된다. 근래의 ID/Password로 인증하는 방식의 웹서비스 또는 정보서비스들은 대부분 개인 PC, 스마트폰, 업무 PC 등에서 접근하는 추세이며, 임의적 장소에서 임의의 기기로 해당 서비스에 접근하는 양상은 과거에 비하여 감소하는 추세다. 이 같은 추세에 따라, 주로 사용하는 기기에 HTML5의 keygen과 Web-Storage 기능을 사용하여 암호화된 Key를 생성하고 저장하여 ID 와 Password가 노출되어도 해당 기기가 아니면 인증되지 않는 시스템을 구현 할 수 있으며 타 기기의 경우 일회성을 갖는 인증 방식을 사용하여, 기존 보다 안전한 인증 시스템을 적은 비용으로 구축 할 수 있다.

• International journal of advanced smart convergence
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• v.8 no.3
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• pp.161-166
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• 2019

Viewed in the rate of change in the web environment, it is very difficult to remain the initial planning at the time until the time of launch, and there is a need for a method to accommodate changes and satisfy market demands during the development process. Unlike the traditional waterfall approach of maintaining initial planning, scrum is one of the agile methodologies that enables flexibility to respond to changes in the market and customers' needs and drive customer satisfaction and business success. However, to apply the scrum to a project in actual, the practice method itself is relatively simple but not easy to apply. The reason is that the members of the organization need to understand and participate in scrum's philosophy and principles and the continuous observation and change management should be carried out. Therefore, in this paper, we presented the feature dashboard and customized scrum methodology to enable continuous observation and change management using visibility, and we shared the case that periodically reflected inspection and adaptation with the explanation of the main points. Also, based on the experience with participants, the strengths and weakness of the feature dashboard and the customized scrum methodology are summarized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.142-146
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• 2014

The mobile computing has been a main mean of computing, because of recent development of smartphone and mobile communication network. The new service technologies, such as cloud computing, big data, SDN (Software Defined Network), and NFV (Network Function Virtualization), are appearing due to activating of the data center. These changes have brought various requirements for transport layer protocol. In addition, the transport protocol should have a extensible function to adapt additional technologies. This paper proposed that transport layer divide into three layer structure for extensible function, and designed the ETP(Extensible Transport Protocol) which is located in the bottom layer.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.279-286
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• 2022

In this paper, we designed a software library that produces integrated Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) navigation information using the raw measurements provided by the GNSS chipset, gyroscope, accelerometer and magnetometer embedded in android smartphone. Loosely coupled integration method was used to derive information of GNSS /INS integrated navigation. An application built in the designed library was developed and installed on the android smartphone. And we conducted field experiments. GNSS navigation messages were collected in the Radio Technical Commission for Maritime Service (RTCM 3.0) format by the Network Transport of RTCM via Internet Protocol (NTRIP). As a result of experiments, it was confirmed that design requirements were satisfied by deriving navigation such as three-dimensional position and speed, course over ground (COG), speed over ground (SOG), heading and protection level (PL) using the designed library. In addition, the results of this experiment are expected to be applicable to maritime navigation applications using smart device.