• The Journal of Asian Finance, Economics and Business
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• 제6권1호
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• pp.129-139
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• 2019

The purpose of this research is to examine the effect of informational justice on post-recovery satisfaction, and the effect of post-recovery satisfaction on behavioral intentions in e-commerce, including further investigate the moderating effect of service failure severity. Using quantitative method, the population of this research are online customers in Indonesia, with non-probability sampling that will be done by purposive sampling method based on predetermined criterias, which are customers who were doing transactions in the Business to Consumer (B2C) online sites, experienced service failure in the last 6 months, submitted a complaint, and received a response. Sample of 317 online customers were gathered and analyzed using the Structural Equation Modeling. The results of this study indicated that 5 hypothesis are supported with data. As a conclusion, informational justice and post-recovery satisfaction has positive effect, while service failure severity acts as a moderator between post-recovery satisfaction and behavioral intentions. As a managerial implication, online store management needs to ensure the informational justice to make a post-recovery satisfaction. Therefore, online store management needs to ensure the informational justice to make a post-recovery satisfaction, increase repurchase and positive e-word of mouth intention, also work harder to recover services, especially in high service failure severity condition.

• Journal of Communications and Networks
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• 제6권3호
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• pp.235-244
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• 2004

There have been a lot of approaches to evaluate and predict transmission control protocol (TCP) performance in a numerical way. Especially, under the recent advance in wireless transmission technology, the issue of TCP performance over wireless links has come to surface. It is because TCP responds to all packet losses by invoking congestion control and avoidance algorithms, resulting in degraded end-to-end performance in wireless and lossy systems. By several previous works, although it has been already proved that overall TCP performance is largely dependent on its loss recovery performance, there have been few works to try to analyze TCP loss recovery performance with thoroughness. In this paper, therefore, we focus on analyzing TCP's loss recovery performance and have developed a simple model that facilitates to capture the TCP sender's behaviors during loss recovery period. Based on the developed model, we can derive the conditions that packet losses may be recovered without retransmission timeout (RTO). Especially, we have found that TCP Reno can retransmit three packet losses by fast retransmits in a specific situation. In addition, we have proved that successive three packet losses and more than four packet losses in a window always invoke RTO easily, which is not considered or approximated in the previous works. Through probabilistic works with the conditions derived, the loss recovery performance of TCP Reno can be quantified in terms of the number of packet losses in a window.

• 한국통신학회논문지
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• 제30권3B호
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• pp.130-137
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• 2005

무선 통신 환경은 WiBro 등과 같은 새로운 무선 통신 기술들을 이용함에 따라 고속 인터넷 접속이 가능하도록 빠르게 변화하고 있다. 이에 따라 무선 구간에서 TCP(Transmission Control Protocol)를 이용한 신뢰성 있는 데이터 전송도 늘어날 전망이다. TCP는 유선상에서 사용될 목적으로 디자인되었기 때문에 유선과 다른 환경, 특히 무선에서 사용될 때에는 비 혼잡 손실에 의해 성능 저하를 겪게 된다. 특히 RTO(Retransmission Timeout)은 TCP의 성능에 많은 영향을 미친다. 본 논문에서는 기존 연구를 바탕으로 손실 복구 확률을 분석하고, 모의실험 결과를 통해 제안 알고리듬이 fast recovery 과정 중에 발생한 패킷 손실을 빠르게 감지하여 RTO없이 복구함으로써 성능 저하를 줄일 수 있음을 보인다.

• 방사선산업학회지
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• 제10권4호
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• pp.199-204
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• 2016

The dependence of cell survival on exposure dose and the duration of the liquid-holding recovery (LHR) was obtained for diploid yeast cells irradiated with ionizing radiation of different linear energy transfer (LET) and recovering from radiation damage without and with various concentrations of cisplatin - the most widely used anticancer drug. The ability of yeast cells to recover from radiation damage was less effective after cell exposure to high-LET radiation, when cells were irradiated without drug. The increase in cisplatin concentration resulted in the disappearance of this difference whereas the fraction of irreversible damage was permanently enlarged independently of radiation quality. The probability of cell recovery was shown to be constant for various conditions of irradiation and recovery. A new mechanism of cisplatin action was suggested according with which the inhibition of cell recovery after exposure to ionizing radiations was completely explained by the production of irreversible damage.

• 디지털콘텐츠학회 논문지
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• 제6권1호
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• pp.41-48
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• 2005

잡음환경이 열악하고 대역폭이 부족한 HFC 망 상향채널에서 보다 나은 대칭형 멀티미디어 서비스를 제공할 수 있는 S-DMT 방식의 상향 채널 케이블모뎀을 위한 심볼 타이밍 복원 알고리즘을 제안하고 그에 대한 성능을 평가하였다. 타이밍 복원 알고리즘은 시간 영역에 PN 시퀀스를 삽입하는 방식을 제안하였으며 AWGN, ISI, 및 임펄스 잡음 환경에서 시뮬레이션을 통해 성능을 평가 하였다. 성능 평가 결과, PN 시퀀스 삽입 알고리즘에 의한 타이밍 복원방식은 잡음 환경에 따라 타이밍 추정 성능이 매우 달라지며, 동일한 샘플링 클럭 오프셋에서 AWGN, ISI, 및 임펄스 잡음이 함께 존재하는 채널일 경우가 임펄스 잡음 채널 경우보다 타이밍 실패 확률이 $10^3$일 때의 Eb/No가 10dB 이상 열화되나 초기부터 샘플링 클럭 오프셋을 보정하여 최적화한 경우 잡음환경에 의한 성능차이가 있으나 비교적 양호한 타이밍 추정 성능을 보임을 확인 하였다.

• 한국해양공학회지
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• 제28권1호
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• pp.69-76
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• 2014

Survivability assessments and vulnerability reductions are required in warship design. A warship's survivability is assessed by its susceptibility, vulnerability, and recoverability. In this paper, an integrated survivability assessment for a warship subjected to multiple hits is introduced. The methodology aims at integrating a survivability assessment into an early stage of warship design. The hull surface is idealized using typical geometries for RCS (Radar Cross Section) detection probability and susceptibility. The Vulnerability is evaluated by using the shot-line. The recoverability is estimated using a survival time analysis. This enables the variation of survivability to be assessed. Several parameters may be varied to determine their effects on the survivability. The susceptibility is assessed by the probability of detecting the radar cross section of the subject and the probability of being hit based on a probability density function. The vulnerability is assessed by the kill probability based on the vulnerable area of critical components, according to the component's layout and redundancy. Recoverability is assessed by the recovery time for damaged critical components.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제19권1호
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• pp.23-45
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• 2015

We consider counterparty risk in CDS rates. To do so, we use a multivariate jump diffusion process for obligors' default intensity, where jumps (i.e. magnitude of contribution of primary events to default intensities) occur simultaneously and their sizes are dependent. For these simultaneous jumps and their sizes, a homogeneous Poisson process. We apply copula-dependent default intensities of multivariate Cox process to derive the joint Laplace transform that provides us with joint survival/default probability and other relevant joint probabilities. For that purpose, the piecewise deterministic Markov process (PDMP) theory developed in [7] and the martingale methodology in [6] are used. We compute survival/default probability using three copulas, which are Farlie-Gumbel-Morgenstern (FGM), Gaussian and Student-t copulas, with exponential marginal distributions. We then apply the results to calculate CDS rates assuming deterministic rate of interest and recovery rate. We also conduct sensitivity analysis for the CDS rates by changing the relevant parameters and provide their figures.

• Journal of Communications and Networks
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• 제13권4호
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• pp.393-399
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• 2011

We evaluate the link-level performance of cooperative multi-hop relaying networks with an maximum distance separable (MDS) code. The effect of the code on the link-level performance at the destination is investigated in terms of the outage probability and the spectral efficiency. Assuming a simple topology, we construct an absorbing Markov chain. Numerical results indicate that significant improvement can be achieved by incorporating an MDS code. MDS codes successfully facilitate recovery of the message block at a relaying node due to powerful error-correcting capability, so that it can reduce the outage probability. Furthermore, we evaluate the average number of hops where the message block can be delivered.

• 인터넷정보학회논문지
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• 제7권1호
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• pp.59-64
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• 2006

GKRS(Global Key Recovery System)는 키복구 기관과 공개키 인증기관(CA)의 기능들을 결합한 시스템이다[1]. GKRS의 다른 특징으로 User-Dominance(즉, 사용자가 자신의 공개-비밀키 쌍과 특히 공개-비밀키 쌍의 유용성을 검증하기 위한 공개 인자(public element)를 선택하도록 한다.)가 GKRS의 광범위한 적용을 위한 아주 중요한 요소로서 제안되었다. 본 논문에서는 CA에 의해 채택된 User-Dominance 방식과 그에 해당하는 키 검증 방식이 CA에 대한 사용자들의 기만 공격을 허용함을 보임으로서 GKRS의 RSA 방식을 공격하고, 이와 같은 공격으로부터 안전한 개선된 GKRS 방식을 제안한다. 제안된 방식은 CA가 랜덤 수를 이용하여 사용자의 기만 공격 확률을 무시할 정도로 작게 함으로서 안전성을 확보하고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권10호
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• pp.5058-5077
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• 2019

Traditional regenerating codes are designed to tolerate node failures with optimal bandwidth overhead. However, there are many types of partial failures inside the node, such as latent sector failures. Recently, proposed regenerating codes can also repair intra-node failures with node-level redundancy but incur significant bandwidth and I/O overhead. In this paper, we construct a new scheme of regenerating codes, called IR-RBT codes, which employs intra-node redundancy to tolerate intra-node failures and serve as the help data for other nodes during the repair operation. We propose 2 algorithms for assigning the intra-node redundancy and RBT-Helpers according to the failure probability of each node, which can flexibly adjust the helping relationship between nodes to address changes in the actual situation. We demonstrate that the IR-RBT codes improve the bandwidth and I/O efficiency during intra-node failure repair over traditional regenerating codes but sacrifice the storage efficiency.