• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.287-292
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• 2019

This paper analyzes the thermal behaviors of genuine discs used in automobiles and discs coming out of tuning products through FEM analysis. Modeling with genuine disk modeling and tuning disks Model-1, Model-2, Model-3 and analyzing the disk rotation speed was set to 1000rpm. When the brake is operated, the thermal behavior of the disk surface, such as the operating temperature caused by the disk and pad contact, the friction surface temperature after the disk stop, and the thermal deformation, were analyzed. When the brake was activated (0-4.5 seconds), the tuning disk showed 34℃ higher than the original disk, and after the disk stopped (40.5 seconds), the tuning disk was analyzed 18℃ lowe, deformation due to the disk heat was deformed by 0.3mm for the tuning disk. Although there is an effect to reduce the fading phenomenon due to the thermal behavior of the pure disk and the tuning disk, it can be observed that there is no significant change in the thermal behavior due to the hole processing and the disk surface processing of the tuning disk.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.215-218
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• 2007

모바일 환경에서는 상향링크와 하향링크의 대역폭이 비대칭적이며 전력이 한정되어 있기 때문에 효율적인 데이터 전송기술로 브로드캐스팅 방법이 연구되어 왔다. 브로드캐스트에서 인덱스를 사용하면 원하는 데이터가 언제 방송되는지를 알 수 있어 튜닝 시간을 줄이고, 전력의 소비를 줄이는 효과가 있다. 지금까지 연구된 싱글 채널 인덱스 기법들은 모든 데이터 아이템이 동일한 확률로 접근되는 flat 브로드캐스트 방송에 적합한 인덱스 기법들이다. 데이터 아이템에 대한 접근 확률이 편향되는 경우에는 멀티디스크 방송 기법을 사용해야 효과적이지만, 기존의 인덱스 기법들은 인덱스가 한 방송 주기 내에서 반복되어 방송되는 데이터 아이템을 가리킬 수 없기 때문에 멀티디스크 방송 기법에는 효과적이지 않다. 본 논문에서는 싱글 채널 인덱스 기법으로서 멀티디스크 방송에 적용되는 인덱스 기법인 MDEI (Multi-disk Exponential Index) 기법을 제안한다. 제안 하는 MDEI 기법은 각 디스크 별로 인덱스를 구성하기 때문에 데이터에 대한 접근확률이 편향되는 경우에 멀티디스크 방송을 기반으로 이 인덱스 기법을 사용하면 flat 브로드캐스트를 사용하는 다른 인덱스 기법을 사용했을 때보다 평균 접근지연시간 시간을 크게 줄일 수 있다. 실험 결과는 데이터에 대한 접근 확률이 편향된 환경에서 MDEI가 평균 접근지연시간에 있어서 매우 좋은 성능을 갖는 것을 보여준다.

• Journal of Auto-vehicle Safety Association
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• v.8 no.3
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• pp.28-32
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• 2016

Braking system is directly related to the safety of a vehicle and the brake discs are essential part of the braking system. Due to the repeated frictional forces and torque during braking, brake discs are always works at high temperature and high pressure. Furthermore, the brake disc is one of major tuning components in aftermarket, the braking performance of the brake disc should be evaluated for establishing the certification standards of tuning components. This paper proposes the test method to evaluate the performance of tuning brake discs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.243-248
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• 2000

하드디스크의 트랙 밀도를 높이기 위해서는 충분한 서보대역을 갖는 액츄에이터를 개발하는 것이 필수적이다 이 논문에서는 액츄에이터의 동특성 중에서 서보대역을 제한하는 주된 요인을 알아보기 위해 실험 모드 해석과 유한 요소 해석을 수행하였다. 우선 액츄에이터를 구성하고 있는 VCM 코일, E 블럭, 서스펜션등의 부분계에 대한 유한 요소 해석을 수행하였고 모달 실험을 통해 이를 검증하였다. 검증된 각 부분계의 모델을 결합하여 한 개의 서스펜션을 갖는 액츄에이터 시스템의 유한 요소 모델을 개발하였고 이를 통해 서보 성능과 관계된 모달 파라미터들을 규명하였다.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.2
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• pp.33-40
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• 2018

In an environment with a large network bandwidth, maximizing bandwidth utilization is an important issue to increase transmission efficiency. End-to-end transfer efficiency is significantly influenced by factors such as network, data transfer nodes, and intranet network security policies. Science DMZ is an innovative network architecture that maximizes transfer performance through optimal solution of these complex components. Among these, the data transfer node is a key factor that greatly affects the transfer performance depending on storage, network interface, operating system, and transfer application tool. However, tuning parameters constituting a data transfer node must be performed to provide high transfer efficiency. In this paper, we propose a method to enhance performance through tuning parameters of 100Gbps data transfer node. With experiment result, we confirmed that the transmission efficiency can be improved greatly in 100Gbps network environment through the tuning of Jumbo frame and CPU governor. The network performance test through Iperf showed improvement of 300% compared to the default state and NVMe SSD showed 140% performance improvement compared to hard disk.

• Journal of KIISE:Databases
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• v.35 no.6
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• pp.518-532
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• 2008

Broadcast scheme has been widely researched for efficient data delivery in the mobile environment because the downlink capacity of a mobile client is much greater than the uplink capacity, and the power of a mobile client is limited. In the proposed scheme, the index lets the client know when data items would be broadcasted and enables the client to minimize the tuning time and power consumption. Single channel index schemes are fit to flat broadcast that performs well when all the broadcasted data items are accessed with the same probability whereas the multi-disk broadcast scheme is proper when the data access distribution is skewed. The existing index schemes, however, cannot work on the Multi-disk broadcast scheme because they cannot point the replicating data items in a broadcast cycle. This paper proposes a Multi-disk Exponential Index (MDEI) which is a single channel index scheme fit to Multi-disk broadcast scheme. Because MDEI scheme organizes a separate index for each disk, it functions with multi-disk broadcast, resulting in a greater reduction of average access latency than that of other flat-broadcast index schemes when the data access distribution is skewed. The performance evaluation showed that MDEI has a good performance when data access distribution is skewed. MDEI has short average access latency and not much average tuning time when the data access distribution is skewed.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.9-16
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• 2015

On modern operating systems such as Linux, virtual memory is a general way to provide a large address space to applications by using main memory and storage devices. Recently, storage devices have been improved in terms of latency and bandwidth, and it is expected that applications with large memory show high-performance if next-generation storage devices are considered. However, due to the overhead of virtual memory subsystem, the paging system can not exploit the performance of next-generation storage devices. In this study, we propose several optimization techniques to extend memory with next-generation storage devices. The techniques are to allocate block addresses of storage devices for write-back operations as well as to configure the system parameters, and we implement the techniques on Linux 3.14.3. Our evaluation through using multiple benchmarks shows that our system has 3 times (/24%) better performance on average than the baseline system in the micro(/macro)-benchmark.