• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.889-891
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• 2009

로봇 어플리케이션의 활용도는 사회 전반에서 점차 확대되고 있지만 로봇들의 컴퓨팅 자원 차이로 인해 한 로봇에서 다양한 어플리케이션을 실행하기는 힘든 실정이다. 본 논문에서는 로봇이 주변장치와의 자원 공유를 통해 자원의 제약을 극복하는 프레임워크를 제안한다. 프레임워크는 협업에 요구되는 공통 구성 요소들을 정의한다. 또한 네트워크로 연결된 로봇과 다양한 장치의 예시를 통해 프레임워크의 동작 흐름을 보인다.

• 한국통신학회논문지
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• 제32권7B호
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• pp.422-430
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• 2007

현재 WDM-PON 기술은 FTTH 구축을 위해 가장 핵심적인 가입자망 기술로 인식되고 있다. 하지만 시스템 비용의 많은 부분을 차지하는 광 송수신기 및 RN과 밀접한 관계가 있는 WDM-PON 시스템 자원의 고정적인 관리방법은 비용 대비 시스템 자원 효율성에 한계점을 가지고 있다. 이에 본 논문에서는 자원의 동적 관리가 가능하면서 이를 위한 시스템의 구축비용 최소화를 이룰 수 있는 WDM-PON 구조를 제안한다. 이를 위해 ONU의 논리그룹화 및 논리그룹 간 파장 공유를 위한 OLT, ONU 그리고 RN의 구조를 설계하고, 이를 기반으로 탄력적인 동적자원 관리를 위한 동적 자원 할당 기법을 제안한다. 이와 같은 WDM-PON 구조의 성능 분석을 위해 모의실험을 수행하였고, 그 결과 논리그룹의 크기와 시스템 구축비용의 상관관계 및 논리그룹 크기와 동적 자원 할당 능력의 상관관계를 도출할 수 있었으며, 자원 관리 기법의 동적 자원 할당 능력과 공평성 유지 능력을 확인할 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제13권3호
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• pp.169-177
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• 2008

그리드 컴퓨팅 환경에서 컴퓨팅 자원은 매우 다양한 네트워크와 시스템으로 구성되어 있다. 이기종의 환경에서 기존의 자원선택 기법으로 사용자가 원하는 자원을 검색 및 선택하는 것은 자원정보의 저장 구조상 한계가 있다. 본 논문은 사용자의 요구사항과 데이터 특성에 맞는 자원을 선택하기 위해 그리드 자원을 온톨로지로 구축하고, SWRL을 이용하여 정의한 규칙을 바탕으로 추론 엔진을 거쳐서 자원을 선택 및 제공하는 온톨로지 기반의 그리드 자원선택시스템을 제안한다. 실험 결과는 본 논문에서 제안한 온톨로지 기반의 그리드 자원선택 시스템이 기존 그리드 자원선택 시스템인 Condor-G와 Nimrod-G 보다 더 높은 작업 처리율 및 자원 이용률과 적은 작업 손실 및 처리 시간을 보임으로써 그리드 자원선택을 지능적이며 능동적으로 할 수 있고, 자원 이용에 더 효과적이라는 사실을 증명한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.3273-3308
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• 2017

Building appropriate trust evaluation models is an important research issue for security guarantee in social networks. Most of the existing works usually consider the trust values at the current time slot, and model trust as the stochastic variable. However, in fact, trust evolves over time, and trust is a stochastic process. In this paper, we propose a novel time-variant stochastic trust evaluation (TSTE) model, which models trust over time and captures trust evolution by a stochastic process. Based on the proposed model, we derive the time-variant bound of untrustworthy probability, which provides stochastic trust guarantee. On one hand, the time-variant trust level of each node can be measured by our model. Meanwhile, by tolerating nodes with relatively poor performance, our model can effectively improve the node resource utilization rate. Numerical simulations are conducted to verify the accuracy and consistency of the analytical bounds on distinguishing misbehaved nodes from normal ones. Moreover, simulation results on social network dataset show the tradeoff between trust level and resource utilization rate, and verify that the successful transmission rate can be improved by our model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.941-955
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• 2015

In dual-channel networks (DCNs), all frequency hopping (FH) sequences used for data channels are chosen from the original FH sequence used for the control channel by shifting different initial phases. As the number of data channels increases, the hitting frequency point problem becomes considerably serious because DCNs is non-orthogonal synchronization network and FH sequences are non-orthogonal. The increasing severity of the hitting frequency point problem consequently reduces the resource utilization efficiency. To solve this problem, we propose a novel hitting frequency point collision avoidance method, which consists of a sequence-selection strategy called sliding correlation (SC) and a collision avoidance strategy called keeping silent on hitting frequency point (KSHF). SC is used to find the optimal phase-shifted FH sequence with the minimum number of hitting frequency points for a new data channel. The hitting frequency points and their locations in this optimal sequence are also derived for KSHF according to SC strategy. In KSHF, the transceivers transmit or receive symbol information not on the hitting frequency point, but on the next frequency point during the next FH period. Analytical and simulation results demonstrate that unlike the traditional method, the proposed method can effectively reduce the number of hitting frequency points and improve the efficiency of the code resource utilization.

• 보건행정학회지
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• 제14권1호
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• pp.121-147
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• 2004

Since the pilot program for a DRG-based prospective payment system was introduced in 1997, the performance of KDRGs has been one of hotly debated issues. The objectives of this study are to refine the classification algorithm of the KDRGs and to assess the improvement achieved by the refinement. The U.S. Medicare DRGs version 17.0 and the Australian Refined DRGs version 4.1 were reviewed to identify areas of possible impro-vement. Refined changes in the classification and result of date analyses were submitted to a panel of 48 physicians for their reviews and suggestions. The refinement was evaluated by the variance reduction in resource utilization achieved by the KDRG The database of 2,182,168 claims submitted to the Health Insurance Review Agency during 2002 was used for evaluation. As the result of the refinement, three new MDCs were introduced and the number of ADEGs increased from 332 to 674. Various age splits and two to four levels of severity classification for secondary diagnoses were introduced as well. A total of 1,817 groups were defined in the refined KDRGs. The variance reduction for charges of all patients increased from 48.2％ to 53.6％ by the refinement, and from 65.6％ to 73.1％ for non-outlier patients. The r-square for length of stays of all patients was increased from 28.3％ to 32.6％, and from 40.4％ to 44.9％ for non-outlier patients. These results indicated a significant improvement in the classification accuracy of the KDRG system.

• Journal of Electrical Engineering and Technology
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• 제10권6호
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• pp.2406-2412
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• 2015

Multi-user multi-input multi-output (MU-MIMO) system has attracted the 4^th generation wireless network as one of core technique for performance enrichment. In this system rate control is a challenging problem and another problem is optimization. Proper scheduling can resolve these problems by deciding which set of user and at which rate the users send their data. This paper proposes a new multi-parameter based scheduling (MPS) for downlink multi-user multiple-input multiple-output (MU-MIMO) system under space-time block coding (STBC) transmissions. Goal of this MPS scheme is to offer improved link level performance in terms of a low average bit error rate (BER), high packet delivery ratio (PDR) with improved resource utilization and service fairness among the user. This scheme allows the set of users to send data based on their channel quality and their demand rates. Simulation compares the MPS performance with other scheduling scheme such as fair scheduling (FS), normalized priority scheduling (NPS) and threshold based fair scheduling (TFS). The results obtained prove that MPS has significant improvement in average BER performance with improved resource utilization and fairness as compared to the other scheduling scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.1-17
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• 2016

The separated management and operation of commercial IP/optical multilayer networks makes network operators look for a unified control plane (UCP) to reduce their capital and operational expenditure. Software-defined networking (SDN) provides a central control plane with a programmable mechanism, regarded as a promising UCP for future optical networks. The general control and scheduling mechanism in SDN-based optical burst switching (OBS) networks is insufficient so the controller has to process a large number of messages per second, resulting in low network resource utilization. In view of this, this paper presents the burst-flow scheduling mechanism (BFSM) with a proposed scheduling algorithm considering channel usage. The simulation results show that, compared with the general control and scheduling mechanism, BFSM provides higher resource utilization and controller performance for the SDN-based OBS network in terms of burst loss rate, the number of messages to which the controller responds, and the average latency of the controller to process a message.

• ETRI Journal
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• 제26권4호
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• pp.321-331
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• 2004

In this paper, we propose a new dynamic bandwidth allocation (DBA) algorithm for multimedia services over Ethernet PONs (passive optical networks). The proposed algorithm is composed of a low-level scheduler in the optical network unit (ONU) and a high-level scheduler in the optical line terminal (OLT). The hierarchical DBA algorithm can provide expansibility and efficient resource allocation in an Ethernet PON system in which the packet scheduler is separated from the queues. In the proposed DBA algorithm, the OLT allocates bandwidth to the ONUs in proportion to the weight associated with their class and queue length, while the ONU preferentially allocates its bandwidth to queues with a static priority order. The proposed algorithm provides an efficient resource utilization by reducing the unused remaining bandwidth caused by the variable length of the packets. We also define the service classes and present control message formats conforming to the multi-point control protocol (MPCP) over an Ethernet PON. In order to evaluate the performance, we designed an Ethernet PON system on the basis of IEEE 802.3ah "Ethernet in the first mile" (EFM) using OPNET and carried out simulations. The results are analyzed in terms of the channel utilization, queuing delay, and ratio of the unused remaining bandwidth.

• 지식경영연구
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• 제15권1호
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• pp.65-84
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• 2014

Organization's innovation capability is strongly tied to its intellectual capital or knowledge utilization. Employees play a key role in generation of intellectual capital and utilization of knowledge in a firm. Thus, the importance of human resource management (HRM) system for enhancing competency of employees and facilitating knowledge sharing between employees is getting its significance. In this paper, we highlighted the effect of HRM implementation to explain the reason of performance differences among firms, adopting the same ideal HRM system. The successful implementation of HRM system as well as the contents of HRM system was critical to enhance firm performance through HRM system. To investigate the effect of HRM implementation on firm performance, we proposed the three components of HRM implementation (i.e.; TMT philosophy, HR department capability and communication) in perspective of sense making and sense giving theory. Then, we analyzed the moderating effect of HRM implementation on the high commitment HRM - firm performance relationship. Empirical results showed that each component of HRM implementation positively strengthened the relationship between high commitment HRM and firm performance. In addition, the composite index of HRM implementation calculated by average value of three components revealed more significant moderating effect between the two. Furthermore, We discussed the academical and practical implications, and suggested future research directions.