• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.933-935
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• 2013

This paper supposes an QoS supporting method based on an efficient subchannel allocation in OFDMA systems. The objective of this paper is to maximize the system throughput while satisfying QoS requirements of mobile multimedia services, comprising real-time and non-real-time services. The resource management for handover are necessary to maintain the QoS requirements of different multimedia applications because the service continuity may be defected by some delay and information loss.

• Annual Conference of KIPS
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• 2002.04a
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• pp.671-674
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• 2002

동적 메모리 할당 방식은 사전에 그 메모리의 크기를 결정할 수 없는 경우에 효과적인 프로그래밍 기술이다. 하지만 메모리 조각화 문제와 최악의 경우 실행 시간을 예측할 수 없는 단점 때문에 실시간 시스템에는 거의 적용되지 않고 있다. 본 연구에서는 리눅스 기반의 실시간 시스템을 위한 동적 메모리 할당 알고리즘인 QB(Ouick-Buddy)를 제안한다 제안된 알고리즘은 작은 크기의 메모리 요구에 대해서 워드 크기별로 프리 리스트를 관리하고, 큰 크기의 메모리 요구에 대해서는 이진 버디 시스템을 이용하여 관리한다. 이 알고리즘에서는 작은 크기의 메모리 요구에 대해 완전-적합(exist-fit) 전략을 사용하여 메모리 이용 효율을 증가시킨다. 또한 큰 크기의 메모리 요구에 대해서 버디 시스템을 적용함으로써 외부 조각화를 제거시키고 처리량(throughput)을 증가시킨다. 제안된 알고리즘의 성능을 확인하기 위해서 제안된 알고리즘과 이진 버디 시스템(binary buddy system), 빠른-적합(quick-fit)의 메모리 이용 효율성 및 메모리 조각화 율을 비교할 것이다.

• Journal of Communications and Networks
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• v.14 no.2
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• pp.130-139
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• 2012

Energy harvesting has emerged as a powerful technology for complementing current battery-powered communication systems in order to extend their lifetime. In this paper a general framework is introduced for the optimization of communication systems in which the transmitter is able to harvest energy from its environment. Assuming that the energy arrival process is known non-causally at the transmitter, the structure of the optimal transmission scheme, which maximizes the amount of transmitted data by a given deadline, is identified. Our framework includes models with continuous energy arrival as well as battery constraints. A battery that suffers from energy leakage is studied further, and the optimal transmission scheme is characterized for a constant leakage rate.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.147-153
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• 2016

In this paper, we propose an efficient dynamic workload balancing strategy which improves the performance of high-performance computing system. The key idea of this dynamic workload balancing strategy is to minimize execution time of each job and to maximize the system throughput by effectively using system resource such as CPU, memory. Also, this strategy dynamically allocates job by considering demanded memory size of executing job and workload status of each node. If an overload node occurs due to allocated job, the proposed scheme migrates job, executing in overload nodes, to another free nodes and reduces the waiting time and execution time of job by balancing workload of each node. Through simulation, we show that the proposed dynamic workload balancing strategy based on CPU, memory improves the performance of high-performance computing system compared to previous strategies.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.125-129
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• 2016

In this paper, we propose an efficient dynamic workload balancing strategy which improves the performance of high-performance computing system. The key idea of this dynamic workload balancing strategy is to minimize execution time of each job and to maximize the system throughput by effectively using system resource such as CPU, memory. Also, this strategy dynamically allocates job by considering demanded memory size of executing job and workload status of each node. If an overload node occurs due to allocated job, the proposed scheme migrates job, executing in overload nodes, to another free nodes and reduces the waiting time and execution time of job by balancing workload of each node. Through simulation, we show that the proposed dynamic workload balancing strategy based on CPU, memory improves the performance of high-performance computing system compared to previous strategies.

• Convergence Security Journal
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• v.5 no.1
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• pp.45-52
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• 2005

In this paper, the development specification of the optical burst switching system (OBS) for next generation internet services is presented. The development specification includes the number of input/output nodes, the number of wavelengths, buffer capacity, the capacity/queue size of the controller and maximum burst assembly delay. From the performance parameters related to the OBS design, an mathematical model to maximize the throughput and minimize the data loss is presented, and then efficient heuristic algorithm is also presented to analyze the sensitivity of the system parameters.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2619-2621
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• 2001

This study proposes a new efficient MAC(media access control) protocol to establish the ultrasonic communication network for under water vehicles, which ensures a certain level of maximum throughput regardless of the propagation delay of ultrasonic and allows fast data transmission through the multiple ultrasonic communication channel. In this study, a media access control protocol for underwater communication network that allows 'peer-to-peer' communication between a surface ship and multiple underwater system is designed, and the proposed control protocol is implementde for its verification.

• Journal of information and communication convergence engineering
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• v.2 no.1
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• pp.15-21
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• 2004

One of the most important issues in designing a network and realizing a service is dealing with traffic characteristics. Recent experimental research on LAN, WAN, and VBR traffic properties has highlighted that real traffic specificities can not be displayed because the current models based on the Poisson assumption under estimate the long range dependency of network traffic and self-similar peculiarities. Therefore, a new approach using self-similarity characteristics as a real traffic model was recently developed. In This paper we discusses the definition of self-similarity traffic. Moreover, real traffic was collected and we generated self-similar data traffic like real traffic to background load. On the existing ABR congestion control algorithm transmission throughput with the representative ERICA, EPRCA and NIST switch algorithm show the efficient reaction about the burst traffic.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.53-60
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• 2021

Many standard methods are used for secret text files and secrete short messages cryptography, these methods are efficient when the text to be encrypted is small, and the efficiency will rapidly decrease when increasing the text size, also these methods sometimes have a low level of security, this level will depend on the PK length and sometimes it may be hacked. In this paper, a new method will be introduced to improve the data protection level by using a changeable secrete speech file to generate PK. Highly Secure Data Encryption (HSDE) method will be implemented and tested for data quality levels to ensure that the HSDE destroys the data in the encryption phase, and recover the original data in the decryption phase. Some standard methods of data cryptography will be implemented; comparisons will be done to justify the enhancements provided by the proposed method.

• BMB Reports
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• v.52 no.10
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• pp.589-594
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• 2019

Single-molecule techniques have been used successfully to visualize real-time enzymatic activities, revealing transient complex properties and heterogeneity of various biological events. Especially, conventional force spectroscopy including optical tweezers and magnetic tweezers has been widely used to monitor change in DNA length by enzymes with high spatiotemporal resolutions of ~nanometers and ~milliseconds. However, DNA metabolism results from coordination of a number of components during the processes, requiring efficient monitoring of a complex of proteins catalyzing DNA substrates. In this min-review, we will introduce a simple and multiplexed single-molecule assay to detect DNA substrates catalyzed by enzymes with high-throughput data collection. We conclude with a perspective of possible directions that enhance capability of the assay to reveal complex biological events with higher resolution.