• 제어로봇시스템학회논문지
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• 제7권10호
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• pp.882-890
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• 2001

The data link layer of Foundation Fieldbus is operated on the basis of scheduling and token-passing disciplines. This paper presents a network design method of Foundation Fieldbus using a bandwidth allocation scheme. Fieldbus traffic consists of periodic data and sporadically generated time-critical and time-available data. The bandwidth allocation scheme schedules the transmission of periodic data. Time-critical and time-available data are transmitted via a token-passing service. The validity of this bandwidth allocation scheme is determined using an experimental model of a network system. The results obtained from the experimental model show that the proposed scheme restricts the delay of both periodic and time-critical data to a pre-specified bound. The proposed bandwidth allocation scheme also fully utilizes the bandwidth resource of the network system.

• Journal of Communications and Networks
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• 제16권4호
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• pp.430-435
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• 2014

The performance of a distributed database system depends particularly on the site-allocation of the fragments. Queries access different fragments among the sites, and an originating site exists for each query. A data allocation algorithm should distribute the fragments to minimize the transfer and settlement costs of executing the query plans. The primary cost for a data allocation algorithm is the cost of the data transmission across the network. The data allocation problem in a distributed database is NP-complete, and scalable evolutionary algorithms were developed to minimize the execution costs of the query plans. In this paper, quadratic assignment problem heuristics were designed and implemented for the data allocation problem. The proposed algorithms find near-optimal solutions for the data allocation problem. In addition to the fast ant colony, robust tabu search, and genetic algorithm solutions to this problem, we propose a fast and scalable hybrid genetic multi-start tabu search algorithm that outperforms the other well-known heuristics in terms of execution time and solution quality.

• Journal of Communications and Networks
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• 제16권5호
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• pp.559-567
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• 2014

In this paper, a framework for power allocation of downlink transmissions in orthogonal frequency division multiple access-based decode-and-forward cellular relay networks is investigated. We consider a system with a single base station communicating with multiple users assisted by multiple relays. The relays have limited power which must be divided among the users they support in order to maximize the data rate of the whole network. Advanced power allocation schemes are crucial for such networks. The optimal relay power allocation which maximizes the data rate is proposed as an upper bound, by finding the optimal power requirement for each user based on knapsack problem formulation. Then by considering the fairness, a new relay power allocation scheme, called weighted-based scheme, is proposed. Finally, an efficient power reallocation scheme is proposed to efficiently utilize the power and improve the data rate of the network. Simulation results demonstrate that the proposed power allocation schemes can significantly improve the data rate of the network compared to the traditional scheme.

• 대한전자공학회논문지
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• 제27권8호
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• pp.1303-1310
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• 1990

This paper describes the design and implementation of a system for automatic data path synthesis in digital system. There are four subtasks to synthesize a digital system: scheduling, register allocation, functional unit allocation and bus allocation. In this paper, force directed algorithm is used for the scheduling while new algorithms are proposed for the allocation subtasks. Synthesis results of two experimental data paths including MC6502 have shown that our proposed algorithm out goes most of previous works.

• 한국정보통신학회논문지
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• 제24권9호
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• pp.1241-1244
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• 2020

In this paper, we consider a downlink non-orthogonal multiple access system with a base station and N mobile stations, where we assume that instantaneous channel state information (CSI) is available at the base station. A power allocation scheme is proposed to achieve perfect fairness, which means equal data rates for all mobile stations. However, the power allocation scheme using full CSI requires high complexity. Hence, a simple power allocation scheme with low complexity is proposed by using high signal-to-noise power ratio (SNR) approximation. The simple power allocation scheme can achieve perfect fairness only for high SNR. However, it needs only the best CSI and the simple procedure to obtain power allocation coefficients. From simulation results, we show that the simple power allocation scheme provides remarkable fairness performance at high SNR.

• International Journal of Computer Science & Network Security
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• 제23권3호
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• pp.31-48
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• 2023

The popularization of smart devices and subsequent optimization of their sensing capacity has resulted in a novel mobile crowdsensing (MCS) pattern, which employs smart devices as sensing nodes by recruiting users to develop a sensing network for multiple-task performance. This technique has garnered much scholarly interest in terms of sensing range, cost, and integration. The MCS is prevalent in various fields, including environmental monitoring, noise monitoring, and road monitoring. A complete MCS life cycle entails task allocation, data collection, and data aggregation. Regardless, specific drawbacks remain unresolved in this study despite extensive research on this life cycle. This article mainly summarizes single-task, multi-task allocation, and space-time multi-task allocation at the task allocation stage. Meanwhile, the quality, safety, and efficiency of data collection are discussed at the data collection stage. Edge computing, which provides a novel development idea to derive data from the MCS system, is also highlighted. Furthermore, data aggregation security and quality are summarized at the data aggregation stage. The novel development of multi-modal data aggregation is also outlined following the diversity of data obtained from MCS. Overall, this article summarizes the three aspects of the MCS life cycle, analyzes the issues underlying this study, and offers developmental directions for future scholars' reference.

• 제어로봇시스템학회논문지
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• 제6권11호
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• pp.943-954
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• 2000

Fieldbus is the lowest level industrial network in the communication hierarchy of factory automation and distributed process control systems. Data generated from field devices are largely divided into three categories : time-critical, periodic and time-available data. Because these data share one fieldbus medium, it needs a method that allocates these data to the bandwidth-limited fieldbus medium. This paper introduces an implementation method of bandwidth allocation scheme on PROFIBUS. In order to implement bandwidth allocation scheme on PROFIBUS, the following functions need to be supplemented on the FDL(Fieldbus Datalink Layer) protocol: (i) separation of medium bandwidth into periodic and non-periodic intervals, (ii) synchronization of node timers over a local link. In order to examine the validity of bandwidth allocation scheme on PROFIBUS, this paper develops an experimental model of a network system. The results obtained from the experimental model show that the bandwidth allocation scheme satisfies the performance requirement of time-critical, periodic and time-available data.

• 산업공학
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• 제24권2호
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• pp.128-138
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• 2011

This research proposes a resource allocation model of Data QC (Quality Control) activities using COQ (Cost of Quality). The model has been developed based on a series of research efforts such as COQ classifications, weight determination of Data QC activities, and an aggregation approach between COQ and Data QC activities. In the first stage of this research, COQ was divided into the four typical classifications (prevention costs, appraisal costs, internal failure costs and external failure costs) through the opinions from five professionals in Data QC. In the second stage, the weights of Data QC activities were elicited from the field professionals. An aggregation model between COQ and Data QC activities has been then proposed to help the practitioners make a resource allocation strategy. DEA (Data Envelopment Analysis) was utilized for locating efficient decision points. The proposed resource allocation model has been validated using the case of Korea national defense information system. This research is unique in that it applies the concept of COQ to the data management for the first time and that it demonstrates a possible contribution to a real world case for budget allocation of national defense information.

• 한국인터넷방송통신학회논문지
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• 제14권5호
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• pp.35-43
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• 2014

데이터 할당 기술은 데이터 방송 시스템의 성능을 향상시키기 위해서 필수적이다. 본 논문은 다중 데이터 질의가 제기되는 환경에서 방송채널에 데이터를 할당하는 주제를 연구하여 DAMA(Data Allocation using Moving Average)로 명명된 새로운 데이터 할당 기법을 제안한다. 제안된 기법은 각 데이터의 방송빈도를 자신의 액세스 확률의 이동 평균에 의해 결정하는 전략을 채택한다. DAMA는 질의 크기에 따라 액세스 확률의 영향력을 적절하게 제어할 수 있기 때문에 질의 응답시간의 성능을 향상시킬 수 있다. 제안된 기법의 성능 평가를 위해 시뮬레이션이 수행되었다. 실험 결과에 따르면, 평균 응답시간의 성능에서 DAMA는 다른 기법보다 우수한 성능을 보인다.

• 한국인터넷방송통신학회논문지
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• 제15권5호
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• pp.75-84
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• 2015

데이터 할당 기술은 데이터 방송 시스템의 성능을 향상시키기 위해서 필수적이다. 본 논문은 질의 프로파일과 질의 요청 확률이 주어진 환경에서 다중 데이터 질의를 처리하기 위하여 방송채널에 데이터를 할당하는 주제를 연구하여 IDAS(Interdependent Dta Allocation Scheme)로 명명된 새로운 데이터 할당 기법을 제안한다. 제안된 기법은 각 데이터의 방송빈도를 자신의 상대적 액세스 확률의 제곱근 값에 비례하게 설정하는 전략을 채택한다. IDAS 기법은 요청 확률이 높은 질의들을 빠르게 처리할 수 있고 적절한 수준의 질의 데이터 인접성을 보일 수 있기 때문에 질의 응답 시간의 성능을 향상시킬 수 있다. 제안된 기법의 성능 평가를 위해 시뮬레이션이 수행되었다. 실험 결과에 따르면, 평균 응답시간의 성능에서 IDAS는 다른 기법보다 우수한 성능을 보인다.