• Journal of KIISE:Information Networking
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• v.35 no.6
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• pp.538-548
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• 2008

In the Internet Engineering Task Force(IETF), Next Step in Signaling(NSIS) working group, proposed a mechanism to discover the Crossover Node(CRN), when the route is changed by Mobile Node(MN) handover. The CRN is divergence or convergence node on old and new path for reserving resources. Trough the CRN discovery mechanism, it possible to reduce a signaling delay and avoid the redundant reservation on the common path between old and new path. However, the QoS(Quality of Service) can be guaranteed continuously while the MN is performing handover, it is needed to pre-reserve the resource on the new path before completion of the handover. When the nodes on the new path try to make a pre-resource reservation before the handover, it is difficult to pre-reserve the resource with the existing CRN discovery mechanism. Therefore, we proposed a Passive CRN(PCRN) discovery scheme and pre-resource reservation mechanism. The PCRN which means an initial common point between the current reserved and the new paths, where the handover can take place.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1163-1166
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• 2007

핸드오버가 발생하는 이동망 환경에서 주요 이슈 중 하나는 핸드오버 후 MN(Mobile Node)의 트래픽이 전송될 새로운 경로 상에 자원 재예약을 위한 지연 시간을 최소화하는 것이다. 이를 위해, 데이터 전달 경로가 변경된 경로에서만 자원예약 시그널링이 이루어지도록 CRN(Crossover Node)을 발견하는 것이 중요하다. 이동망 환경에서 자원 재예약을 위한 CRN은 SID(Session ID)를 이용하여 발견될 수 있다. 그러나 HMIPv6 네트워크에서 MAP(Mobility Anchor Point)과 HA(Home Agent)간 군집(Aggregate) 자원 예약이 이루어진 경우에서는 SID를 이용하여 CRN을 발견할 수 없다. 왜냐하면, MN의 핸드오버 후, 종단간 SID는 동일할지라도 이전 MAP과 HA간 설립된 세션의 군집 SID가 새로운 MAP과 HA간 설립된 세션의 군집 SID와 다르기 때문이다. 이에, 본 논문에서는 HMIPv6 네트워크에서의 CRN 발견방안을 제안한다. 제안하는 방안에서는 시그널링 메시지에 이전 군집 세션 정보를 포함하여 전달함으로서 시그널링 메시지가 목적지까지 도달하기 전에 CRN이 발견될 수 있도록 하였다. 제안하는 방안은 군집 자원예약이 갖는 시그널링 및 플로우별 상태 정보 감소 효과를 그대로 유지하면서, MN의 핸드오버 후, 자원 재예약을 위한 지연 시간을 단축시킴으로서 통신 성능을 향상 시킬 수 있을 것으로 기대된다.

• Korean Journal of Plant Resources
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• v.21 no.4
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• pp.336-340
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• 2008

Corilagin (CRN) isolated from Euphorbia helioscopia as rheumatoid arthritis drug. CRN was medicated to the abdominal cavity of collagen induced arthritis (CIA) mice that was an animal model for rheumatoid arthritis and its effects on incidence and arthritis index were studied. The results were as folllows; It was exhibited that medicating corilagin inhibited the infiltration of activated T lymphocytes into an inflammatory joint. The production of IgG and IgM that were RF (rheumatoid factor) and inflammatory cytokine, IL-6 and $TNF-{\alpha}$were reduced. After measuring $IFN-{\gamma}$and IL-4, it was found that it was shifted into Th2 immune response as increasing in IL-4. After liver function test, studies on liver poisoning of AST/ALT should be continued.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.79-86
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• 2015

Cognitive radio networks (CRNs) offer the promise of intelligent radios that can learn from and adapt to their environment. CRN permits unlicensed users to utilize the idle spectrum as long as it does not introduce interference to the primary users due to the Federal Communications Commission's recent regulatory policies. Thereby, the security aspects in CRNs should be different with the other networks. The purpose of this paper is to devise a new delegation-based authentication protocol (NDAP) by extracting out the security aspects for unlicensed user authentication over CRNs from Tsai et al's delegation-based authentication protocol (TDAP). First of all, we will provide security analyses on the TDAP and set design goal for unlicensed user authentication. Then, we will propose a NDAP as a remedy mechanism for the TDAP and a new protocol for CRNs. The NDAP could be used as a security building block for the CRNs and various convergence applications.

• Journal of Korean Biological Nursing Science
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• v.22 no.3
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• pp.213-221
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• 2020

Purpose: The purpose of this study was to explore the role performance and related factors of clinical research nurses (CRN) in the process of clinical trials of new drug development. Methods: Study participants were CRN whose affiliation was in non-capital areas and who had been working longer than three months at the time of the data collection. The data collection was conducted with a semi-structured questionnaire development by Hwang & Go, 2011 comprising 16 items of participants' characteristics and 60 items of role performance via in-person and online. Additionally, opinions which would be necessary to establish the CRN role were questioned for the future. A total of 141 questionnaires of 151 questionnaires responses were analyzed using descriptive statistics, t-test, and ANOVA for data analysis as appropriate. Results: The level of overall role performance was above average (5.61±0.90) with the highest in subject care (6.04 ± 0.96) and management and the lowest in self-development (4.39 ± 1.52). The only factor affecting overall role performance was employment status and the only sub-category affected by factors of employment status, and some general characteristics was self-development. Conclusion: From study results, it can be concluded that the CRN seem to perform their proper role. Nonetheless, self-development should be considered as critical aspect for better CRN competency, which is an important aspect toward improving the CRN role performance. Additionally, efforts to improve the level of role performance must be established through stable employment and concrete departmental placement as suggested in this study.

• Journal of information and communication convergence engineering
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• v.15 no.2
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• pp.79-84
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• 2017

In a cognitive radio network (CRN), cognitive radio users (CUs) should be powered by a small battery for their operations. The operations of the CU often include spectrum sensing and data transmission. The spectrum sensing process may help the CU avoid a collision with the primary user (PU) and may save the energy that is wasted in transmitting data when the PU is present. However, in a time-slotted manner, the sensing process consumes energy and reduces the time for transmitting data, which degrades the achieved throughput of the CRN. Subsequently, the sensing process does not always offer an advantage in regards to throughput to the CRN. In this paper, we propose a scheme to find an optimal policy (i.e., perform spectrum sensing before transmitting data or transmit data without the sensing process) for maximizing the achieved throughput of the CRN. In the proposed scheme, the data collection period is considered as the main factor effecting on the optimal policy. Simulation results show the advantages of the optimal policy.

• ETRI Journal
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• v.38 no.3
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• pp.444-454
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• 2016

Voice service is very demanding in cognitive radio networks (CRNs). The available spectrum in a CRN for CR users varies owing to the presence of licensed users. On the other hand, voice packets are delay sensitive and can tolerate a limited amount of delay. This makes the support of voice traffic in a CRN a complicated task that can be achieved by devising necessary considerations regarding the various network functionalities. In this paper, the support of secondary voice users in a CRN is investigated. First, a novel packet scheduling scheme that can provide the required quality of service (QoS) to voice users is proposed. The proposed scheme utilizes the maximum packet transmission rate for secondary voice users by assigning each secondary user the channel with the best level of quality. Furthermore, an analytical framework developed for a performance analysis of the system, is described in which the effect of erroneous spectrum sensing on the performance of secondary voice users is also taken into account. The QoS parameters of secondary voice users, which were obtained analytically, are also detailed. The analytical results were verified through the simulation, and will provide helpful insight in supporting voice services in a CRN.

• Convergence Security Journal
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• v.21 no.1
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• pp.209-219
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• 2021

The problem of congestion in the licensed radio channels spectrum can be solved by Cognitive Radio Networks (CRN). Several algorithms exist to ensure the rendezvous between Secondary Users (SUs), they are increasingly efficient, allowing faster rendezvous under multiple scenarios. In parallel, several jamming algorithms are developed to counter rendezvous which are also improving. The goal in CRN is to ensure the rendezvous by warding such jammers with robust algorithms. In this paper, we classify various jamming techniques and analyze the performance of various well-known rendezvous algorithms under jamming attacks.

• Biomedical Science Letters
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• v.27 no.4
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• pp.216-222
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• 2021

Colorectal cancer (CRC) is major cancer with high incidence and mortality worldwide. It is known that most CRCs arise from precursor adenomatous polyps (APs). Recently, microRNA (miRNA) has been proposed as a biomarker for various cancers including CRC. In this study, the expression patterns of miR-29a in the whole blood (WB) of CRC, AP, and control groups were analyzed by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) to evaluate the expression level of miR-29a in patients with colorectal neoplasm (CRN) including CRC and AP. As a result, the relative expression of miR-29a was significantly decreased in the patients with CRN compared to the control group (P<0.001). The results were in agreement with previous in vitro cell studies and studies that used tissue and feces samples, suggesting that miR-29a in WB may be useful in demonstrating the status of colorectal tissue. Additionally, we divided the control group into healthy control (HC) without any colorectal symptoms and non-tumor control (NTC) with colorectal symptoms but without any CRN. And then the relative expression of miR-29a was also significantly decreased in the NTC group compared to the HC group (P<0.001). Therefore, our study revealed that miR-29a can differentiate patients with CRN from HC group, but they are also involved in the early stage of inflammatory response and cannot be specific biomarkers for CRN.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.744-761
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• 2016

For about the past decade and a half research efforts into cognitive radio networks (CRNs) have increased dramatically. This is because CRN is recognized as a technology that has the potential to squeeze the most out of the existing spectrum and hence virtually increase the effective capacity of a wireless communication system. The resulting increased capacity is still a limited resource and its optimal allocation is a critical requirement in order to realize its full benefits. Allocating these additional resources to the secondary users (SUs) in a CRN is an extremely challenging task and integer programming based optimization tools have to be employed to achieve the goals which include, among several aspects, increasing SUs throughput without interfering with the activities of primary users. The theory of the optimization tools that can be used for resource allocations (RA) in CRN have been well established in the literature; convex programming is one of them, in fact the major one. However when it comes to application and implementation, it is noticed that the practical problems do not fit exactly into the format of well established tools and researchers have to apply approximations of different forms to assist in the process. In this survey paper, the optimization tools that have been applied to RA in CRNs are reviewed. In some instances the limitations of techniques used are pointed out and creative tools developed by researchers to solve the problems are identified. Some ideas of tools to be considered by researchers are suggested, and direction for future research in this area in order to improve on the existing tools are presented.