• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.662-665
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• 2001

As the fuzzy control is applied to servo system the hardware implementation of the fuzzy information systems requires the high speed operations, short real time control and the small size systems. The aims of this study is to develop hardware of the fuzzy information systems to be apply to servo system. In this paper, we propose a calculation method of approximate reasoning for fuzzy control based on $\alpha$-level set decomposition of fuzzy sets by quantize $\alpha$-cuts. This method can be easily implemented with analog hardware. The influence of quantization levels of $\alpha$-cuts on output from fuzzy inference engine is investigated. It is concluded that 4 quantization levels give sufficient result for fuzzy control performance of do servo system. It examined useful with experiment for dc servo system.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.113-116
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• 2000

Phase noise of oscillator gives the performance degradation significantly when a high carrier frequency and low transmission rate are used. The BER(Bit Error Rates) degradation of QPSK(Quadrature Phase Shift Keying) transmission is analyzed with the oscillator phase noise level specified in downstream physical interface of LMDS(Local Multipoint Distribution Services) which is described in DAVIC(Digital Audio Visual Council). The model used for the phase noise is a power-law model. We also investigated the effects of the various transmission rates on system performance. For the transmission rate below 0.5 Mbps, the BER performance is severely degraded and we verified that the transmission rate, 20 Mbps, is adequate for the downstream of LMDS systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.763-777
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• 2021

Information security started as an IT operation process and is now recognized as an important issue of information technology, and each international organization is newly defining the concept. Information security itself is a new combination of IT technologies, a set of technologies and a technology area. As IT outsourcing becomes common in many public sectors, SLAs are introduced to evaluate the level of IT services. In the area of information security, many studies have been conducted on the derivation and selection of SLA performance indicators, but it is difficult to find a way to apply the performance indicators to service level evaluation and performance systems. This thesis conducted a study on the application of a service evaluation system for information security performance indicators based on the public sector and a performance system including compensation regulations. It presents standards and rewards(incentive and penalty) that define expectation and targets of performance indicators that take into account the environment and characteristics of a specific public sector, and defines appropriate SLA costs. It proposes a change plan for the organizational structure for practical SLA application and service level improvement.

• Journal of Information Processing Systems
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• v.18 no.1
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• pp.159-172
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• 2022

The role of the interconnect network, which connects computing nodes to each other, is important in high-performance computing (HPC) systems. In recent years, the peripheral component interconnect express (PCIe) has become a promising interface as an interconnection network for high-performance and cost-effective HPC systems having the features of non-transparent bridge (NTB) technologies. OpenSHMEM is a programming model for distributed shared memory that supports a partitioned global address space (PGAS). Currently, little work has been done to develop the OpenSHMEM library for PCIe-interconnected HPC systems. This paper introduces a prototype implementation of the OpenSHMEM library through a switchless interconnect network using PCIe NTB to provide a PGAS programming model. In particular, multi-interrupt, multi-thread-based data transfer over the OpenSHMEM shared memory model is applied at the implementation level to reduce the latency and increase the throughput of the switchless ring network system. The implemented OpenSHMEM programming model over the PCIe NTB switchless interconnection network provides a feasible, cost-effective HPC system with a PGAS programming model.

• Journal of KIISE:Software and Applications
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• v.26 no.1
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• pp.80-80
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• 1999

As Temporal DataBase Systems(TDBSs) manages both the historical versions and the current version of each data item, a temporal transaction may access more data records than atransaction in traditional database systems. Hence, the concurrency control subsystem of temporaldatabase management system should be able to correctly and efficiently detect actual conflicts amongconcurrent temporal transactions while the cost of detecting conflicts is maintained in low levelwithout detecting false conflicts which cause severe degradation of system throughput.In this paper, Two-Level Conflict Detection(TLCD) scheme is proposed for efficient conflictdetection between concurrent temporal transactions in TDBs. In the proposed TLCD scheme, sincechecking conflict between concurrent temporal transactions is performed at two levels, i, e., logicallevel and physical level, conflicts between concurrent temporal transactions are efficiently and correctlydetected,Furthermore, we also evaluate the performance of the proposed TLCD scheme with those oftraditional conflict detection schemes, logical-level conflict detection scheme and physical-level conflictdetection scheme by simulation approach, The result of the simulation study shows that the proposedTLCD scheme outperforms the previous conflict detection schemes with respect to the averageresponse time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3602-3620
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• 2016

Dynamic topology is one of the main influence factors on network performability. However, it was always ignored by the traditional network performability assessment methods when analyzing large-scale mobile ad hoc networks (MANETs) because of the state explosion problem. In this paper, we address this problem from the perspective of complex network. A two-layer hierarchical modeling approach is proposed for MANETs performability assessment, which can take both the dynamic topology and multi-state nodes into consideration. The lower level is described by Markov reward chains (MRC) to capture the multiple states of the nodes. The upper level is modeled as a small-world network to capture the characteristic path length based on different mobility and propagation models. The hierarchical model can promote the MRC of nodes into a state matrix of the whole network, which can avoid the state explosion in large-scale networks assessment from the perspective of complex network. Through the contrast experiments with OPNET simulation based on specific cases, the method proposed in this paper shows satisfactory performance on accuracy and efficiency.

• Asia pacific journal of information systems
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• v.25 no.3
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• pp.597-625
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• 2015

Prior research has emphasized the significant effect of service orientation on organizational performance. However, little research on service orientation has been conducted in the financial field, including the investment management service industry in which high quality service for clients is required. In this paper, we propose a research model that centers on the concept of service orientation as a type of dynamic capability affecting firm performance. The research variables include job competency, risk management capability, operational capability, service orientation, and service performance. We assume that service orientation partially mediates the effects of risk management capability and operational capability on service performance. To test the model, we collected data from 391 fund managers in 86 teams (37 investment management companies) and analyzed it with partial least squares (PLS) method. Each of the 391 fund managers was asked to answer team level measures, which is effective for team level analysis. We find that job competency positively affects both risk management capability and operational capability, which in turn affect service orientation. Risk management capability and operational capability are assumed to directly affect service performance. However, risk management capability does not influence perceived service performance, whereas operational capability does affect it. This result indicates that risk management capability does not directly affect service performance. However, via service orientation, considering that risk management inconveniences customers and is geared to enhance service orientation, service performance is positively affected. Operational capability does not influence service orientation, whereas it affects perceived service performance. This result reveals that operational capability directly affects firm performance. As expected, service orientation significantly affects the service performance perception of fund managers. This study contributes to the literature by introducing service orientation to the financial industry and measures and tests team-level service performance. Our findings also provide insights to practitioners because to enhance team performance, managers must focus on service orientation in addition to operational capability.

• Information Systems Review
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• v.9 no.2
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• pp.149-168
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• 2007

As the need for quantitative qualities of IT investment performance heightens, numerous research organizations are developing various measurement methods for the quantitative evaluation and its currency value conversion. Corporations utilizing these methods to evaluate IT investment performance are gradually increasing. However, working-level staff in the corporations that have introduced the quantitative evaluation can not assure if the evaluation sufficiently reflects the actual effect provided by IT since the results arising from the conversion of currency value can't be visibly confirmed. This study tries to identify whether the quantitative evaluation of IT investment performance can be explained in terms of the level of consumer satisfaction proven by the qualitative evaluation by analyzing the level of consumer satisfaction and quantitative evaluation of a case company and identifying the correlation between them. As the result of the case study, the following points have been concluded. Firstly, the currency value of IT effect correlates with the level of consumer satisfaction. Secondly, in order to come up with a rational currency value of IT effect, developing an indicator as well as managing data on currency conversion that will enable the internal system's efficiency to become more quantitative is essential. Thirdly, IT ROI is not appropriate to compare the performance between systems and is utilized as a measurement standard for each system's performance and efficiency. Lastly, quantitative evaluation is still inadequate in the evaluation of the system's strategic side, and consumer satisfaction can be utilized as a supplementary method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1599-1606
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• 1997

The software RAID file system is defined as the system which distributes data redundantly across an aray of disks attached to each workstations connected on a high-speed network. This provides high throughput as well as higher availability. In this paper, we present an efficient caching scheme for the software RAID filte system. The performance of this schmem is compared to two other schemes previously proposed for convnetional file systems and adapted for the software RAID file system. As in hardware RAID systems, small-writes to be the performance bottleneck in softwre RAID filte systems. To tackle this problem, we logically divide the cache into two levels. By keeping old data and parity val7ues in the second-level cache we were able to eliminate much of the extra disk reads and writes necessary for write-back of dirty blocks. Using track driven simulations we show that the proposed scheme improves performance for both the average response time and the average system busy time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.273-279
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• 2007

I evaluate the BER performance of OFDM systems in frequency selective Doppler time variant fading channels, considering the pilot patterns for channel estimation. The performance of the systems is degraded due to channel estimation error. For the reduction of performance degradation in acceptable level, the optimum distance of pilot symbols in pilot pattern is 5 subcarriers in frequency domain and 6 OFDM block in time domain.