• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1082-1092
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• 2008

In wireless sensor networks, clustering protocol such as LEACH is an efficient method to increase whole networks lifetime. However, this protocol result in high energy consumption at the cluster head node. Hence, this protocol must changes the cluster formation and cluster head node in each round to prolong the network lifetime. But this method also causes a high amount of energy consumption during the set-up process of cluster formation. In order to improve energy efficiency, in this paper, we propose a new cluster formation algorithm. In this algorithm, we define a intra cluster as the sensor nodes within close proximity of each other. In a intra cluster, a node senses and transmits data at a time on the round-robin basis. In a view of whole network, intra cluster is treated as one node. During the setup phase of a round, intra clusters are formed first and then they are re-clustered(network cluster) by choosing cluster-heads(intra clusters). In the intra cluster with a cluster-head, every member node plays the role of cluster-head on the round-robin basis. Hence, we can lengthen periodic round by a factor of intra cluster size. Also, in the steady-state phase, a node in each intra cluster senses and transmits data to its cluster-head of network cluster on the round-robin basis. As a result of analysis and comparison, our scheme reduces energy consumption of nodes, and improve the efficiency of communications in sensor networks compared with current clustering methods.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.193-204
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• 2006

In most existing distributed Web systems, incoming requests are distributed to servers via Domain Name System (DNS). Although such systems are simple to implement, the address caching mechanism easily results in load unbalancing among servers. Moreover, modification of the DNS is necessary to load considering the server's state. In this paper, we propose a new dynamic load balancing method using dynamic DNS update and round-robin mechanism. The proposed method performs effective load balancing without modification of the DNS. In this method, a server can dynamically be added to or removed from the DNS list according to the server's load. By removing the overloaded server from the DNS list, the response time becomes faster. For dynamic scheduling, we propose a scheduling algorithm that considers the CPU, memory, and network usage. We can select a scheduling policy based on resources usage. The proposed system can easily be managed by a GUI-based management tool. Experiments show that modules implemented in this paper have low impact on the proposed system. Furthermore, experiments show that both the response time and the file transfer rate of the proposed system are faster than those of a pure Round-Robin DNS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.373-376
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• 2003

This paper presents a new, three-dimensional round-robin scheduler that provides high throughput and fair across in an advanced input-queued packet switch using shared input buffers. We consider an architecture in which each input port group shares a common buffer and maintains a separate queue for each output, which is ratted the distributed common input buffer switch. In an NxN switch, our scheduler determines which queue in the total MxN input queues is served during each time slot where M is the number of common buffers. We suppose that each common buffer has K input ports and K output ports, and manages N output queues. The 3DRR scheduler determines MxK queues in every K(M) cycle when $K\geq$M (K$\leq$M), and provides massively parallel processing for the applications of high-speed switches with a large number of ports. The 3-DRR scheduler can be implemented using duplicated simple logic components allowing very high-speed implementation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.87-92
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• 2020

Although GPGPU (General-Purpose GPU) can maximize performance by parallelizing a task with tens of thousands of threads, those threads are internally grouped into a thread block, which is a base unit for processing and resource allocation. A thread block scheduler is a specialized hardware gadget whose role is to allocate thread blocks to GPGPU processing hardware in a round-robin manner. However, round-robin is a sequential allocation policy and is not optimized for GPGPU resource utilization. In this paper, we propose a thread block scheduler model which can analyze and quantify performances for various thread block scheduling policies. Experiment results from the implemented simulator of our model show that the legacy hardware thread block scheduling does not behave well when workload becomes heavy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.177-182
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• 2018

The home-and-way round-robin sports leagues scheduling problem with minimum brake is very hard to solve in polynomial time. This problem is NP-hard, the complexity status is not yet determined. This paper suggests round-robin sports leagues scheduling algorithm not computer-aided program but by hand with O(n) time complexity for arbitrary number of teams n with always same pattern. The algorithm makes a list of mathes using $n{\times}n$ canonical latin square for n=even teams. Then trying to get home(H) and away(A) with n-2 minimum number of brakes. Also, we get the n=odd scheduling with none brakes delete a team own maximum number of brakes from n=even scheduling.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.9
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• pp.50-57
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• 2011

Conventional bus system architectures are composed of several components such as master, arbiter, decoder and slave modules. The arbiter plays a role in bus arbitration according to the selected arbitration method, since several masters cannot use the bus concurrently. Typical priority strategies used in high performance arbiters include static priority, round robin, TDMA and lottery. Typical arbitration algorithms always consider the bus priority primarily, while the bus utilization is always ignored. In this paper, we propose an arbitration method using bus utilization for the operating block of each master. We verify the performance compared with the other arbitration methods through the TLM(Transaction Level Model). Based on the performance verification, the conventional fixed priority and round-robin arbitration methods cannot set the bus utilization. Whereas, in the case of the conventional TDMA and lottery arbitration methods, more than 100,000 cycles of bus utilization can be set by the user, exhibiting differences of actual bus utilization up to 50% and 70%, respectively. On the other hand, we confirm that for the proposed arbitration method, the matched bus utilization set by the user was above 99% using approximately 1,000 cycles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.567-575
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• 2011

The two most popular virtual machine allocation schemes, both match making and round robin, do consider hardware specifications such as CPU, RAM, and HDD, but not CPU usage, which results in balanced resource distribution, but not in balanced resource usage. Thus, in this paper a new virtual machine allocation scheme considering current CPU usage rate is proposed while retaining even distribution of node resources. In order to evaluate the performance of the proposed scheme, a cloud computing platform composed of three cloud nodes and one front end is implemented. The proposed allocation scheme was compared with both match making and round robin schemes. Experimental results show that the proposed scheme performs better in even distribution of overall CPU usage, which results in efficient load balancing.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.469-471
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• 2003

본 논문에서는 그리드 컴퓨팅 시스템 성능 향상을 위해 기존의 스케줄링의 단점인 최악대기시간 문제를 보완한, 작업(Job) 크기에 따른 이중 큐 작업선택 기법을 제안한다. 제안된 기법은 작업의 크기에 따라 이들을 서로 다른 큐에 넣은 후, 라운드 로빈(Round-Robin) 방식으로 작업을 처리함으로써, 그리드 컴퓨팅 시스템 최악 대기시간 성능을 개선시켰다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.256-258
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• 2005

현대 사회에서 무선 인터넷의 활용 분야가 날로 확대되어 가고 있으나 낮은 대역폭, 단말기 해상도의 다양성 등의 여러 가지 근본적인 문제들을 가지고 있다. 이러한 문제를 해결하기 위하여 무선인터넷 프록시 서버를 사용하며, 데이터에 대한 압축과 캐싱 방법을 사용한다. 캐싱 관점에서 해시의 사용은 캐시의 히트율(Hit ratio)을 높이며, 캐시간 협동성(Cooperative Caching)도 가지게 한다. 그러나 기존의 해시기반 스케줄링 알고리즘에서 사용자의 요청이 균등하게 분배되지 못하고 일부 서버로 몰리는 문제점을 가지고 있다. 본 논문에서는 해시 테이블을 이용한 라운드로빈 방식과 캐시 이용률을 이용한 스케줄링 방식을 제안하여, 캐시간 협동성과 사용자의 요청을 고르게 분포 시키도륵 하였다. 16대의 컴퓨터를 이용하여 실험을 수행하였고, 실험결과를 통해 제안된 방식이 기존 방식보다 클라이언트의 요청을 캐시 서버들 사이로 균일하게 분포시키고 이에 따라 전체 무선 인터넷 프록시 서버의 성능이 향상됨을 확인하였다.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.13-16
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• 2001

In the practical sense, it is important to assess the Young modulus and the degradation of $I_{c}$ due to mechanical deformation in HTS tapes for designing superconducting magnets. In order to establish a test method of mechanical properties in oxide composite superconductors, the committee of VAMAS/TWA 16-Subgroup proposed an international round robin test. The first effort has been focused on the multifilamentary Bi-2223 tapes. Eight groups participated in the RRT activity and each group carried out the tensile test by their own professional technique to three kinds of Bi-2223 tapes. The experimental details were reported and discussed for your information.