• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1379-1397
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• 2013

We consider a system where a licensed radio spectrum is shared by multiple primary users(PUs) and secondary users(SUs). As the spectrum of interest is licensed to primary network, power and channel allocation must be carried out within the cognitive radio network so that no excessive interference is caused to PUs. For this system, we study the joint beamforming and power allocation problem via game theory in this paper. The problem is formulated as a non-cooperative beamforming and power allocation game, subject to the interference constraints of PUs as well as the peak transmission power constraints of SUs. We design a joint beamforming and power allocation algorithm for maximizing the total throughput of SUs, which is implemented by alternating iteration of minimum mean square error based decision feedback beamforming and a best response based iterative power allocation algorithm. Simulation results show that the algorithm has better performance than an existing algorithm and can converge to a locally optimal sum utility.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.80-88
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• 2006

The purpose of this thesis is to research and propose a practical Information Security Technical Architecture on Primary Defense Information Infrastructure with regard to requirement of information security. The scope of this research is limited to national defense information master plan & security rule, and U.S. DoD's IATF is used to plan a detailed structure. The result of this research can be used as a guide book for providing security for Army IT infrastructure now and in the future as well as to devise a plan for research and development in information protection technology.

• Journal of Communications and Networks
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• 제16권5호
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• pp.485-492
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• 2014

Spectrum sensing for cognitive-radio applications may use a matched-filter detector (in the presence of full knowledge of the signal that may be transmitted by the primary user) or an energy detector (when that knowledge is missing). An intermediate situation occurs when the primary signal is imperfectly known, in which case we advocate the use of a linear-quadratic detector. We show how this detector can be designed by maximizing its deflection, and, using moment-bound theory, we examine its robustness to the variations of the actual probability distribution of the inaccurately known primary signal.

• International Journal of Computer Science & Network Security
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• 제21권5호
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• pp.168-174
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• 2021

The Cognitive radio (CR) is evolving technology for managing the spectrum bandwidth in wireless network. The security plays a vital role in wireless network where the secondary users are trying to access the primary user's bandwidth. During the allocation the any malicious user either he pretends to be primary user or secondary user to access the vital information's such as credentials, hacking the key, network jam, user overlapping etc. This research paper discusses on various types of attack and to prevent the attack in cognitive radio network. In this research, secondary users are identified by the primary user to access the primary network by the secondary users. The secondary users are given authorization to access the primary network. If any secondary user fails to provide the authorization, then that user will be treated as the malicious user. In this paper two approaches are suggested one by applying elliptic curve cryptography and the other method by using priority-based service access.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.769-773
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• 2013

Background: A literature review on 1,104,269 cancer patients concluded that the prevalence of multiple primary malignancies (MPM) is between 0.73% and 11.7%. MPMs seem to have higher incidence than that influenced by hazard only. The purpose of this study was to investigate clinically useful information for effective screening for synchronous and metachronous second primary cancers and to identify a potential surveillance protocol. Materials and Methods: Using statistical and epidemiological indicators we evaluated the patients with MPMs (double locations) admitted to Dr. Abdurrahman Yurtarslan Ankara Oncology Education and Research Hospital between 1981 and 2010. Results: Out of the 130 cases, 24 (18.4%) were synchronous while 106 cases (81.6%) were metachronous tumours. Mean interval time from first to second primary cancers was 4.65 years (0-27 years). The most frequent malignant associations were breast-breast, breast-endometrium and breast-ovary. Both primary and secondary tumors tended to be in an advanced stage explained by the low compliance of the patients to follow-up. Conclusions: The possibility that MPMs exist must always be considered during pretreatment evaluation. Screening procedures are especially useful for the early detection of associated tumors, whereas careful monitoring of patients treated for primary cancer and a good communication between patients and medical care teams should ensure early detection of secondary tumors, and subsequent appropriate management.

• Journal of Communications and Networks
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• 제14권5호
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• pp.471-480
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• 2012

Reliable detection of primary user activity increases the opportunity to access temporarily unused bands and prevents harmful interference to the primary system. By extracting a global decision from local sensing results, cooperative sensing achieves high reliability against multipath fading. For the effective combining of sensing results, which is generalized by a likelihood ratio test, the fusion center should learn some parameters, such as the probabilities of primary transmission, false alarm, and detection at the local sensors. During the training period in supervised learning, the on/off log of primary transmission serves as the output label of decision statistics from the local sensor. In this paper, we extend unsupervised learning techniques with an expectation maximization algorithm for cooperative spectrum sensing, which does not require an external primary transmission log. Local sensors report binary hard decisions to the fusion center and adjust their operating points to enhance learning performance. Increasing the number of sensors, the joint-expectation step makes a confident classification on the primary transmission as in the supervised learning. Thereby, the proposed scheme provides accurate parameter estimates and a fast convergence rate even in low signal-to-noise ratio regimes, where the primary signal is dominated by the noise at the local sensors.

• 한국정보처리학회논문지
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• 제6권11호
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• pp.3077-3085
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• 1999

Conventional caching system doesn't support Real-Time attributes and load balance. To solve these problems, this paper describes the design and implementation of the RIOP(Real-Time Inter-ORB Protocol) to provide QoS guarantees mechanism integrating RSVP and TAO ORB. Futhermore, it provides fast XCSLS(Extended Caching System for Load Balance) implementing main memory cache in Primary Server using locality of objects. In this paper, a key feature is presented : QoS enforcement, PS(Primary Server) and RS(Replicated Server)

• 충청수학회지
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• 제20권4호
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• pp.457-463
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• 2007

We show that any filter of Tarski algebra can be de-composed into the union of some sets. Moreover, we introduce the notion of expansions of filters in Tarski algebras, and discuss the notion of ${\sigma}$-primary filters in Tarski algebras. Finally, we show that there is no non-trivial quadratic Tarski algebras on a field X with $|X|{\geq}3$.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (1)
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• pp.271-273
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• 1998

본 논문에서는 최근 발달된 컴퓨터 버전의 이미지 처리 기법들을 활용하여 이미지의 기본 속성(primary features)을 정의하고 이미지 검색에서의 효용성을 실험을 통하여 분석한 결과를 제시한다. 기본 속성으로는 색상, 질감, 모자익, 위치정보등을 선정하여 샘플 이미지들에 대한 속성값들을 데이터베이스로 저장하고 시각 질의들을 처리하는 검색 시스템 원형을 구현하여 실험하였다. 정의된 4가지 기본적 속성 중 색상, 질감, 모자익을 이용하는 내용 기반 검색이 기존 시스템과 비교하여 검색 적중률이 향상됨을 보였다. 제안된 이미지의 기본 속성들을 이용하면 실제 이미지 데이터베이스에 대한 질의 처리에 활용할 수 있는 인덱스를 구성할 수 있을 것이다.

• 정보교육학회논문지
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• 제15권3호
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• pp.399-411
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• 2011

초등 중학생을 대상으로 하는 인터넷 및 휴대폰 중독 요인에 대한 기존 연구에서는 집착, 자기효능감, 자기통제력 등 개인적 요인과 부모, 친구, 학교, 지역사회, 대중 매체와 같은 환경적인 요인 등을 제시하였다. 이들 연구는 대부분 학생을 중심으로 자기 자신이나 부모, 친구, 학교, 사회와 같이 상호작용 대상을 중심으로 하였다. 최근, 시간관에 대한 중요성이 강조되면서 여러 영역에서 이에 대한 연구가 시작되었는데, 아직 교육 영역에서 시간관을 다루는 연구는 거의 없다. 본 논문에서는 시간관에 대한 개념을 기술하고 초등 및 중학생들의 시간관이 인터넷 휴대폰 중독의 관점에서 어떤 영향을 미치지는 지를 살펴본다. 이를 위해 619명의 초등 중학생을 대상으로 설문을 실시한 후, 그 결과를 제시한다. 이를 통해 두 중독에 대한 관련 요인들의 상대적 중요도를 재조명하고 두 가지 중독에 대한 예방 방법을 제언한다.