• Journal of Applied Reliability
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• v.17 no.3
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• pp.246-255
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• 2017

Purpose: This study proposes the optimal PM (preventive maintenance) policy of leased equipment for lessee's decision-making using two types of reliability condition. Methods: We consider reliability threshold based PM model. Equipment reliability is estimated and used as condition variable. The effect of repair for maintenance is imperfect and represented by age reduction factor. Results: We provide two PM policies. Policy 1 is focused on minimized total cost. This policy guarantees reliability threshold until last maintenance action. Policy 2 focus on maintaining reliability threshold during leased period. The proposed approach provides optimal reliability threshold under number of PM. Through result, we finally construct decision-making process for lessee using reliability threshold and end of reliability. Conclusion: This study provides two PM policy for lessee's decision-making. Through numerical example, we get a result of optimal reliability threshold, number of PM, optimum alternative under lessee's reliability condition.

• Journal of Communications and Networks
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• v.5 no.1
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• pp.82-89
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• 2003

In this paper, an efficient threshold-based filtering (TF) buffer management scheme is proposed. The TF is capable of minimizing the overall loss performance and improving the fairness of buffer usage in a shared buffer packet switch. The TF consists of two mechanisms. One mechanism is to classify the output ports as sctive or inactive by comparing their queue lengths with a dedicated buffer allocation factor. The other mechanism is to filter the arrival packets of inactive output ports when the total queue length exceeds a threshold value. A theoretical queuing model of TF is formulated and resolved for the overall packet loss probability. Computer simulations are used to compare the overall loss performance of TF, dynamic threshold (DT), static threshold (ST) and pushout (PO). We find that TF scheme is more robust against dynamic traffic variations than DT and ST. Also, although the over-all loss performance between TF and PO are close to each other, the implementation of TF is much simpler than the PO.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.79-83
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• 2004

The purpose of ATM traffic management is to protect the network using minimum resources and guarantee the requred QoS and also it is desirable to provide fairness between input channels. In this paper, we propose the TBBM(threshold based buffer management) algorithm to improve fairness between input channels and utilization of ATM networks. TBBM algorithm controls output cell rate dynamically based on threshold. The result shows that the required bandwidth of the TBBM algorithm is 14.3% lower in audio traffic and 41.8% lower in video traffic than that of theoretically calculated equivalent capacity method. and also reveals that the TBBM algorithm provide improved CLR fairness between input channels

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.769-774
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• 2009

디지털 기술의 발달과 급진적인 IT 산업의 발전은 환경적 인프라의 통합 및 구축을 촉진시켰으며, 이를 기반으로 한 모바일 기기들의 기술적 통합 (Technology Convergence)을 통하여 테크노매드 (Technomad)와 같은 이동성향을 가진 사용자들이 등장하기 시작하였다. 모바일 컨버전스 디바이스에 대한 사용자들의 니즈 (Needs)는 점차 증가추세를 보이고 있으나, 모바일 컨버전스 디바이스의 수요는 캐즘을 넘지 못하여 시장에서 성공적으로 진입하지 못하고 있는 실정이다. 모바일 컨버전스 디바이스를 통해서 얻을 수 있는 디지털 서비스의 구축이 미비한 부분도 있기는 하지만, 만족스럽지 못한 사용성이나, 기기의 도메인적 특성의 불명확함은 기술이나 성능의 수용 민감도가 높은 선각수용자 (Early Adopter)들의 사용에서만 그치게 하는 등의 한계점을 가지고 있다. 이에 본 연구는 모바일 컨버전스 디바이스의 개념과 도메인적 특성을 조사하고, 이를 통하여 사용 임계값 (Threshold)이 매스유저 (Mass User)가 모바일 컨버전스 디바이스를 사용하는데 진입장벽의 원인으로 작용하는 것을 발견하였다. 이러한 사용 임계값 (Threshold)이 실제 태스크 (Task)수행 시 미치는 영향을 파악하기 위하여 휴리스틱과 선각수용자 (Early Adopter)의 웹 기반 조사를 실시하였고, 사용 임계값 (Threshold)의 영향으로 제대로 사용이 이루어지지 않는 태스크 타입 (Task Type)에 따라 시간적, 물리적 사용 임계값 관리 (Threshold Management)가 필요함을 발견하였다. 이를 개선하기 위해 실제 사용자들의 사용을 FGI (Focused Group Interview) 및 Contextual Inquiry 등의 정성적인 사용자 조사방법을 실시하여, 사용자에게 모바일 컨버전스 디바이스를 통하여 만족스런 사용성 및 경험을 제공하기 위해서는 시간적, 물리적, 시야적 사용 임계값 관리 (Threshold Management)를 개선 해야 함을 밝혀내고 결론적으로 이에 대한 가이드라인을 도출하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.897-913
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• 2016

Threshold signature is very important in identity authentication and some other applications. In December 2010, Chinese Encryption Administration released the SM2 elliptic curve digital signature algorithm as the first standard of the digital signature algorithm in China. At present, the papers on the threshold signature scheme based on this algorithm are few. A SM2 elliptic curve threshold signature scheme without a trusted center is proposed according to the Joint-Shamir-RSS algorithm, the Joint-Shamir-ZSS algorithm, the sum or diff-SS algorithm, the Mul-SS algorithm, the Inv-SS algorithm and the PM-SS algorithm. The proposed scheme is analyzed from correctness, security and efficiency. The correctness analysis shows that the proposed scheme can realize the effective threshold signature. The security analysis shows that the proposed scheme can resist some kinds of common attacks. The efficiency analysis shows that if the same secret sharing algorithms are used to design the threshold signature schemes, the SM2 elliptic curve threshold signature scheme will be more efficient than the threshold signature scheme based on ECDSA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.474-485
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• 2002

To keep simplicity that needs for GFR service and improve fairness of FIFO based buffer management algorithm, we propose a new LBO threshold decision mechanism. Proposed mechanism uses dynamic threshold that are adjusted according to the sum of active VC's weight. We reformed DT-DFBA(Differential Threshold-Differential Fair Buffer Allocation) algorithm using proposed LBO threshold decision mechanism with existing DFBA algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2597-2615
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• 2013

This paper proposes a dynamic downlink load control scheme that jointly employs dynamic load threshold management and virtual coverage management schemes to reduce the degree of performance degradation due to traffic overload in two-tier femtocell networks. With the proposed scheme, the downlink load in a serving macrocell is controlled with a load threshold which is adjusted dynamically depending on the varying downlink load conditions of neighboring macrocells. In addition, traffic overloading is alleviated by virtually adjusting the coverage of the overloaded serving macrocell, based on the adjusted load threshold of the serving macrocell. Simulation results show that the proposed scheme improves the performance of two-tier femtocell networks in terms of the outage probability and sum throughput. This improvement is significantly increased with appropriate values of load thresholds and with an intermediate-level adjustment of the virtual coverage area (i.e., handover hysteresis margin: HOM). Furthermore, the proposed scheme outperforms both a previously proposed load control scheme with a static load threshold and the LTE system without a HOM adjustment.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.1-10
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• 1995

In this study, a threshold policy is considered for the M/M/2 queueing system with server vacations. The probability generating function for the number of customers present in the system is derived using an embedded Markov chain approach. Then, assuming a linear cost structure, an efficient procedure to find an optimal threshold policy is presented. The Laplace-Stieltjes transofrm for th waiting time of an arbitrary customer under a "FIFO" discipline is also derived.o derived.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.65-72
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• 2001

With the recent rising project complexities and competitive environments in the construction projects, a risk management is recognized as more important management tool than the others. However, as most risk management techniques applied to the construction projects are centered around their initial phases and risk analyses, they are not developed into general project management technique such as time management, cost management and quality management, etc., that are usually applied in the process of construction. Thus, this paper proposes a response process to construction project risks based on the risk threshold and its calculation methodology applying a concept of VaR to establish risk management as general management technique in the construction projects.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.161-173
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• 2020

This study examines the nonlinear relationship between financial development and economic growth in Pakistan using the threshold regression model for the period 1980-2017. We also employed quantile regression with 0.25, 0.50, and 0.75 quantiles of conditional distribution. The quantile regression is based on minimizing of sum of squared residuals. The result indicates that economic growth responds positively to financial development when the level of financial development surpasses the threshold value of 0.151. However, when financial development lies below the threshold value (that is, 0.151), its impact on economic growth is negative. Thus, when financial development of Pakistan surpasses the threshold level, it contributes more towards economic growth since greater level of financial development contributes more to boosts economic growth. This finding reveals that economic growth reacts differently to financial development, and the relationship between financial development and economic growth is U-shaped in Pakistan. Among the other variables, physical capital, labor force, and government expenditure exert a positive effect on economic growth. Furthermore, inflation rate and trade openness have an insignificant impact on economic growth. The results of quantile regression also confirm the non-linear relationship between financial development and economic growth in Pakistan. The finding of this study suggests revamping of financial sector policies in Pakistan.