• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.33-47
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• 2015

Cellular Network assisted device-to-device (D2D) communication has been growing to reduce the overload of eNodeB and mitigate the frequency shortage. However, by sharing the uplink frequency resource with the cellular network, the interference between cellular and D2D is increased. In this paper, we propose an advanced receiver for full suppression cancellation (FSC) to reduce the interference between cellular and D2D. The proposed receiver can suppress and cancel the interference by integrating the interference rejection combining (IRC) technique with successive interference cancellation (SIC). We perform a system level simulation based on the 20-MHz bandwidth of the 3GPP LTE-A system. Simulation results show that the proposed receiver can improve SINR, throughput and spectral efficiency compared to conventional receivers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.181-188
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• 2011

With the rapid proliferation of wireless networks and mobile computing applications, the landscape of the network security has greatly changed recently. Especially, Vehicular Ad Hoc Networks maintaining network topology with vehicle nodes of high mobility are self-organizing Peer-to-Peer networks that typically have short-lasting and unstable communication links. VANETs are formed with neither fixed infrastructure, centralized administration, nor dedicated routing equipment, and vehicle nodes are moving, joining and leaving the network with very high speed over time. So, VANET-security is very vulnerable for the intrusion of malicious and misbehaving nodes in the network, since VANETs are mostly open networks, allowing everyone connection without centralized control. In this paper, we propose a weighted intrusion detection method using rough set that can identify malicious behavior of vehicle node's activity and detect intrusions efficiently in VANETs. The performance of the proposed scheme is evaluated by a simulation study in terms of intrusion detection rate and false alarm rate for the threshold of deviation number ${\epsilon}$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.10
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• pp.987-994
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• 2011

This paper presents An efficient method of antenna placement considering EMI(Electromagnetic Interference) between equipments which are mounted on the UAV(Unmanned Air Vehicle). The analysis is accomplished for voice communication radio, control datalink, TCAS(Traffic Alert Collision & Avoidance System) and GPS(Global Positioning System) which are vulnerable to EMI because the frequencies are close to each other. There are two steps for analysis procedure : The first one is selecting antenna position on the UAV by monitoring return loss and pattern variation of each antenna. The second one is analyzing EMI via antennas between equipments. In the EMI analysis, spurious level of each transmitter, coupling level between antennas and system noise property are considered. This procedure can be used to predict EMI between equipments in development stage.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.4
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• pp.112-120
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• 2006

Multicarrier code division multiple access(MC-CDMA) system that combines multicarrier modulation with CDMA offers robustness to frequency selective fading and can support higher rate data transmission with higher spectral efficiency. A new asynchronous MC-CDMA system to implement multiple data rate communications is proposed in this paper. In a W-CDMA downlink the orthogonal variable spreading factor(OVSF) code is used for variable spreading factor for various multimedia traffic. Proposed system utilizes the OVSF code that generated by generation property for spreading. The proposed MC-CDMA system use different lengths of OVSF code as a spreading code according to their data rate. The groupwise processing is accomplished by code grouping in OVSF code generation tree. For the analysis of average BER performance, numerical method and computer simulation were used. We also compare the system performance with that of a single rate MC-CDMA system used orthogonal code as a spreading code.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.159-163
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• 2009

CAT(Catchment hydrologic cycle Analysis Tool)은 기존 개념적 매개변수 기반의 집중형 수문모형과 물리적 매개변수 기반의 분포형 수문모형의 장점을 최대한 집약하여, 도시유역 개발 전 후의 장 단기적인 물순환 변화 특성을 정량적으로 평가하고 물순환개선시설의 효과적인 설계를 지원하기 위한 물순환 해석 모형이다. CAT은 수문학적으로 균일하게 판단되는 범위를 소유역으로 분할하여 지형학적 요인에 의한 유출 특성을 객관적으로 반영할 수 있으며, 개발 공간 단위별로 침투, 증발, 지하수 흐름 등의 모의가 가능하도록 하는 Link-Node 형식으로 개발되었다. 모형의 UI(User Interface)는 사용자가 손쉽게 모형을 적용 관리하고, 여러 시나리오를 동시에 효과적으로 모의하여 분석할 수 있도록 설계되었다. 또한 모든 입력 출력 자료를 Excel이나 텍스트 형식과 연동되도록 하여 프로젝트별 매개변수 관리가 용이하도록 개발하였다. CAT의 수문해석모듈로 증발산, 침투, 유역 유출, 지하수 유거, 하도추적 등의 모듈을 개발하였다. 증발산은 기준 증발산을 외부에서 직접 입력하거나, Penman-Monteith 방법을 선택할 수 있으며, 침투는 토양의 수리전도도에 따른 연직방향 침투 및 사면방향 복귀류를 고려할 수 있다. 노드의 지하수 유거를 고려하여 기존 노드-링크 방식 모형의 장기 유출 해석시 제한점을 보완하였으며, 하도추적을 위해 Muskingum, Muskingum-Cunge, Kinematic wave 방법 등의 해석법을 제공하였다. CAT의 수문모듈을 이용하여 설마천 유역을 단일노드 및 멀티노드로 개념화하여 모의하였으며, 모의결과를 관측유량과 비교한 결과, 두 경우 적절한 범위내의 결과임을 확인할 수 있었다. CAT의 안정적인 수문해석 기능을 바탕으로 향후 물순환개선시설 모듈과의 결합을 통해 장기 물순환 해석에 광범위하게 활용될 수 있을 것으로 판단된다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.108-117
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• 2007

RConsumer Portal is defined as "a combination of hardware and software that enables two-way communication between energy service providers(ESP, like KEPCO) and equipment within the consumer's premises". The portal provides both a physical link(between wires, radio waves, and other media) and a logical link(translating among language-like codes and etiquette-like protocols) between in-building and wide-area access networks. Thus, the consumer portal is an important, open public shared infrastructure in the future vision of energy services. This paper presents an XML based standard specification of service-oriented, open protocol for consumer portal system architecture. In the framework level, the XML protocol provides a useful bridge between services and platforms. The proposed standard protocol has been implemented into our developing consumer portal pilot system. The results imply the potential of global standards for consumer portal system by its minimum overhead in network and processor. The reposed XML is designated psXML in this paper.

• The KIPS Transactions:PartB
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• v.11B no.4
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• pp.509-516
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• 2004

Semantic interpretation of image is incomplete without some mechanism for understanding semantic content that is not directly visible. For this reason, human assisted content-annotation through natural language is an attachment of textual description to image. However, keyword-based retrieval is in the level of syntactic pattern matching. In other words, dissimilarity computation among terms is usually done by using string matching not concept matching. In this paper, we propose a method for computerized semantic similarity calculation In WordNet space. We consider the edge, depth, link type and density as well as existence of common ancestors. Also, we have introduced method that applied similarity measurement on semantic image retrieval. To combine wi#h the low level features, we use the spatial color distribution model. When tested on a image set of Microsoft's 'Design Gallery Line', proposed method outperforms other approach.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.9
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• pp.405-412
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• 2013

Current web has evolved to a mashed-up format according to the change of the implementation and usage patterns. Web services and user experiences have improved, however, security threats are also increased as the web contents that are not yet verified combine together. To mitigate the threats incurred as an adverse effect of the web development, we need to check security on the combined web contents. In this paper, we propose a scheduling method to detect malicious web pages not only inside but also outside through extended links for secure operation of a web site. The scheduling method considers several aspects of each page including connection popularity, suspiciousness, and check elapse time to make a decision on the order for security check on numerous web pages connected with links. We verified the effectiveness of the security check complying with the scheduling method that uses the priority given to each page.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.484-490
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• 2016

Full-duplex communication can enhance wireless capacity by enabling simultaneous transmission and reception of the signals on the same frequency spectrum. Such a benefit, however, is only achieved when strong self-interference is well canceled below a sufficient level. To achieve this goal, there have been several approaches for cancellation, each of which is combined with digital-domain cancellation for a higher gain. In this paper, we implement two self-interference cancellation techniques and integrate them with a software defined radio-based wireless communication testbed. Two cancellation techniques (antenna cancellation and noise subtraction) are implemented and the cancellation gain is measured via real experiments. The results show that the gain of the antenna placement technique highly depends on the placement of a receiving antenna and the highest gain is achieved at the expected point, and we show that combining the noise subtraction circuit with the antenna placement further improves the cancellation gain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.10-15
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• 2017

Research interest has strongly focused on developing a method for effectively transmitting bio-signals over a distance using a wireless wearable device. In this paper, we describe a procedure for the design and fabrication of a wearable antenna based on embroidering conductive threads to clothing capable of transmitting electrocardiogram signals. 3D electromagnetic simulation software and embroidery software were used to design and fabricate the conductive thread-based antenna, respectively. The measurement results show that the reflection coefficient of the fabricated antenna prototype exhibits excellent antenna impedance matching characteristics of less than -10dB in the Zigbee 2.4GHz frequency band. We also verified that the electrocardiogram data could be effectively received and monitored in real-time by a receiver 220m away from the transmitter.