• KIPS Transactions on Computer and Communication Systems
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• v.8 no.6
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• pp.127-138
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• 2019

The data response speed is a critical issue of cloud services because it directly related to the user experience. As such, the in-memory database is widely adopted in many cloud-based applications for achieving fast data response. However, the current implementation of the in-memory database is mostly based on the linked list-based hash table which cannot guarantee the constant data response time. Thus, cuckoo hashing was introduced as an alternative solution, however, there is a disadvantage that only half of the allocated memory can be used for storing data. Subsequently, bucketized cuckoo hashing (BCH) improved the performance of cuckoo hashing in terms of memory efficiency but still cannot overcome the limitation that the insert overhead. In this paper, we propose a data management solution called Wall Cuckoo which aims to improve not only the insert performance but also lookup performance of BCH. The key idea of Wall Cuckoo is that separates the data among a bucket according to the different hash function be used. By doing so, the searching range among the bucket is narrowed down, thereby the amount of slot accesses required for the data lookup can be reduced. At the same time, the insert performance will be improved because the insert is following up the operation of the lookup. According to analysis, the expected value of slot access required for our Wall Cuckoo is less than that of BCH. We conducted experiments to show that Wall Cuckoo outperforms the BCH and Sorting Cuckoo in terms of the amount of slot access in lookup and insert operations and in different load factor (i.e., 10%-95%).

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3037-3039
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• 2005

The AIS(Automatic Identification System) transmits the position of ships and other information to prevent accidents which could occur in the sea. It has to be developed SOTDMA(Self-Organized Time Division Multiple Access) Algorithm which is important on wireless communication method for the AIS because It is based on ITU(International Telecommunication Union) M.1371-1 of the international standard therefore, we need to develop a performance evaluation simulator efficiently to develop and analyze SOTDMA Algorithm. this paper shows the method of designing it. Real ships access The VHF maritime mobile band but in this performance evaluation simulator several ship objects access the shared memory. Real ships are designed as the object and the wireless communication channel is designed as the shared memory. The ships apply for real virtual data which got from assistance hardware and The SOTDMA Algorithm driving state verifies the performance evaluation simulator by IEC(International Electrotechnical commission) 61993-2. After verifying results the performance evaluation simulator is correctly satisfied with IEC 61993-2. So we expect that it helps not only the AIS technology developed but also verify new SOTDMA Algorithm

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.478-480
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• 2005

The AIS(Automatic Identification System) transmits the position of ships and other information to prevent accidents which could occur in the sea. It has to be developed SOTDMA(Self-Organized Time Division Multiple Access) Algorithm which is important on wireless communication method for the AIS because It is based on ITU(International Telecommunication Union) M.1371-1 of the international standard therefore, we need to develop a performance evaluation simulator efficiently to develop and analyze SOTDMA Algorithm. This paper shows the method of designing it. Real ships access The VHF maritime mobile band but in this performance evaluation simulator several ship objects access the shared memory. Real ships are designed as the object and the wireless communication channel is designed as the shared memory. The ships apply for real virtual data which got from assistance hardware and The SOTDMA Algorithm driving state verifies the performance evaluation simulator by IEC(International Electrotechnical commission) 61993-2. After verifying results the performance evaluation simulator is correctly satisfied with IEC 61993-2. So we expect that it helps not only the AIS technology developed but also verify new SOTDMA Algorithm.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.31-34
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• 2002

There are two kinds of network architectures in the IEEE 802.11:[1] distributed (ad-hoc) or centralized (infrastructure) wireless network. Centralized networks have an access point (base station) that can control the wireless medium access of stations in these networks. The 802.11 MAC protocol of an access point is the same as those of other stations in the contention period. This paper propose a novel MAC protocol of an access point to solve these problems. This MAC protocol adds a new contention-free period called EPCF (Extended PCF) to resolve accumulated data in the queue of an access point. Simulation results show that the new protocol performs better throughput than the 802.11 standard MAC with the less queue memory site requirement.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.52-52
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.137.1-137.1
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.89.2-89.2
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.135.2-135.2
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• 2007

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.05a
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• pp.114-114
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• 2001

• Journal of the KSME
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• v.25 no.2
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• pp.137-140
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• 1985

이글에서는 마이크로프로세서의 원리와 응용에 관하여 다음의 사항을 중심으로 알아보았다. 1. 마이크로프로세서의 작동원리 - 인텔 8086, 기타 마이크로 프로세서의 작동 (1) 인터럽트(Interrupt) (2) 대기(wait) (3) DMA(Direct Memory Access)