• Title/Summary/Keyword: hit problem

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A Study on Management Functions of Intelligent Reflectors Environment (지능형 반사경의 관리 기능 연구)

  • Kang-Hyun Nam
    • The Journal of the Korea institute of electronic communication sciences
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    • v.18 no.3
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    • pp.433-440
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    • 2023
  • When the reflector is hit by a vehicle or returned by a storm, an event is generated by the impact sensor and a trigger is operated. The trigger processing algorithm of this paper compares the X, Y, and Z values of the gyro sensor with the registered values and proposes to drive them to the original values by the operation of the 3-axis driving motor. And by recognizing the vehicle license plate, if the vehicle is stolen or a social problem, information is provided to the police operation network. When the reflector is stolen or moved, it has a registered GPS value, so it operates the theft monitoring function to process it.

An Effective P2P Searching Algorithm Based on Leveled OK Mechanism (단계별 OK 기법 기반 효과적 P2P 검색 알고리즘)

  • kim Boon-Hee;Lee Jun-Yeon
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.2 s.34
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    • pp.69-78
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    • 2005
  • As the study and use of P2P systems are diversified, the effect of excessive amount of traffic, which occurs in searching peers' resource and is considered as a network bandwidth Problem, cannot let the matter Pass without making a protest. In case P2P application doesn't reduce network traffic, it can be much effected to use bandwidth smoothly in the internet environment where various network applications lie scattered and there will be inconvenience when many network users makes use of related applications . In this Paper, we propose a pure P2P model based-broadcasting technique for producing successful hit ratio and traffic amount in the weakly connected environment based-P2P system where situation of peers' connection and exit is ambiguous . The proposed searching technique is designed/implemented to improve a resident problem in the related system and we have estimated the performance of the proposed searching technique comparing our technique with the existing broadcasting based-searching technique .

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Assessment of Stability of Stability of Hydraulic Breaker Cylinder and Piston through Thermal-Structural coupled Field Analysis by Finite Element Method (유한요소법을 이용한 유압브레이커 Cylinder와 Piston의 열-구조 연성해석을 통한 안정성 평가)

  • Lim, Dong-Wook;Park, Yoon-Soo;Shin, Bong-Cheol
    • Design & Manufacturing
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    • v.12 no.1
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    • pp.41-46
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    • 2018
  • This study proves the causes of cylinder and piston jam by scratches which is the fatal problem of hydraulic breaker through the thermal analysis and thermal-structural coupled field analysis. The trouble from the scratch is a complex problem which can be caused by manufacturing process (this is an internal factor) and the users mistake or contamination in the hydraulic circuit (these are an external factor). Hence, it's not easy to investigate the causes, also hard to prevent the recurrence. In this reason, hydraulic breaker manufacturers are trying to improve the manufacturing process such as machining, heat treatment, grinding, cleaning, also to prevent the contamination in hydraulic circuit and to remove the remains. It's being managed thoroughly by manufacturers. This study shows the effect of the temperature rise by the frictional heat generated when the piston hits the tool on the hydraulic oil while the hydraulic breaker is operating, also the temperature distribution when it starts to affect main components of hydraulic breaker. The stress and the amount of deformation also could be found through thermal-structural coupled field analysis. It proved that the stress and deformation are proportionally increased according to the temperature rise in hit area, and it affects the cylinder and the viscosity of hydraulic oil inside the cylinder when it heats up beyond the certain temperature.

Performance Impact of Large File Transfer on Web Proxy Caching: A Case Study in a High Bandwidth Campus Network Environment

  • Kim, Hyun-Chul;Lee, Dong-Man;Chon, Kil-Nam;Jang, Beak-Cheol;Kwon, Tae-Kyoung;Choi, Yang-Hee
    • Journal of Communications and Networks
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    • v.12 no.1
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    • pp.52-66
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    • 2010
  • Since large objects consume substantial resources, web proxy caching incurs a fundamental trade-off between performance (i.e., hit-ratio and latency) and overhead (i.e., resource usage), in terms of caching and relaying large objects to users. This paper investigates how and to what extent the current dedicated-server based web proxy caching scheme is affected by large file transfers in a high bandwidth campus network environment. We use a series of trace-based performance analyses and profiling of various resource components in our experimental squid proxy cache server. Large file transfers often overwhelm our cache server. This causes a bottleneck in a web network, by saturating the network bandwidth of the cache server. Due to the requests for large objects, response times required for delivery of concurrently requested small objects increase, by a factor as high as a few million, in the worst cases. We argue that this cache bandwidth bottleneck problem is due to the fundamental limitations of the current centralized web proxy caching model that scales poorly when there are a limited amount of dedicated resources. This is a serious threat to the viability of the current web proxy caching model, particularly in a high bandwidth access network, since it leads to sporadic disconnections of the downstream access network from the global web network. We propose a peer-to-peer cooperative web caching scheme to address the cache bandwidth bottleneck problem. We show that it performs the task of caching and delivery of large objects in an efficient and cost-effective manner, without generating significant overheads for participating peers.

Cache Management using a Adaptive Parity Group Configuration in RAID 5 Controller (적응형 패리티 그룹 구성을 이용한 RAID 5 제어기에서의 캐시 운영)

  • Huh, Jung-Ho;Song, Ja-Young;Chang, Tae-Mu
    • The KIPS Transactions:PartA
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    • v.10A no.2
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    • pp.83-92
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    • 2003
  • RAID 5 is a widely-used technique used to construct disk systems of high reliability and performance. This paper proposes APGOC (Adaptive Parity Group On Cache) organization on cache to solve "small write" problem of RAID 5 especially in OLTP (On-Line Transaction Processing System) environments. In our approach, when user process makes a request for a file to kernel, the information on the read/write characteristics is added to the file data structure of the file system. With this information, data and parity cache can be managed interchangeably through parity fetching. Therefore we can enhance the cache utilization and improve the disk request response time. Our method is analyzed and evaluated with a simulation method. Comparing with previous works, we observed about 6~l3% of performance enhancement.hancement.

Block Replacement Scheme based on Reuse Interval for Hybrid SSD System (Hybrid SSD 시스템을 위한 재사용 간격 기반 블록 교체 기법)

  • Yoo, Sanghyun;Kim, Kyung Tae;Youn, Hee Yong
    • Journal of Internet Computing and Services
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    • v.16 no.5
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    • pp.19-27
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    • 2015
  • Due to the advantages of fast read/write operation and low power consumption, SSD(Solid State Drive) is now widely adopted as storage device of smart phone, laptop computer, server, etc. However, the shortcomings of SSD such as limited number of write operations and asymmetric read/write operation lead to the problem of shortened life span of SSD. Therefore, the block replacement policy of SSD used as cache for HDD is very important. The existing solutions for improving the lifespan of SSD including the LARC scheme typically employ the LRU algorithm to manage the SSD blocks, which may increase the miss rate in SSD due to the replacement of frequently used block instead of rarely used block. In this paper we propose a novel block replacement scheme which considers the block reuse interval to effectively handle various data read/write patterns. The proposed scheme replaces the block in SSD based on the recency decided by reuse interval and age along with hit ratio. Computer simulation using workload trace files reveals that the proposed scheme consistently improves the performance and lifespan of SSD by increasing the hit ratio and decreasing the number of write operations compared to the existing schemes including LARC.

Core-aware Cache Replacement Policy for Reconfigurable Last Level Cache (재구성 가능한 라스트 레벨 캐쉬 구조를 위한 코어 인지 캐쉬 교체 기법)

  • Son, Dong-Oh;Choi, Hong-Jun;Kim, Jong-Myon;Kim, Cheol-Hong
    • Journal of the Korea Society of Computer and Information
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    • v.18 no.11
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    • pp.1-12
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    • 2013
  • In multi-core processors, Last Level Cache(LLC) can reduce the speed gap between the memory and the core. For this reason, LLC has big impact on the performance of processors. LLC is composed of shared cache and private cache. In computer architecture community, most researchers have mainly focused on the management techniques for shared cache, while management techniques for private cache have not been widely researched. In conventional private LLC, memory is statically assigned to each core, resulting in serious performance degradation when the workloads are not fairly distributed. To overcome this problem, this paper proposes the replacement policy for managing private cache of LLC efficiently. As proposed core-aware cache replacement policy can reconfigure LLC dynamically, hit rate of LLC is increases drastically. Moreover, proposed policy uses 2-bit saturating counters to improve the performance. According to our simulation results, the proposed method can improve hit rates by 9.23% and reduce the access time by 12.85% compared to the conventional method.

The Early Write Back Scheme For Write-Back Cache (라이트 백 캐쉬를 위한 빠른 라이트 백 기법)

  • Chung, Young-Jin;Lee, Kil-Whan;Lee, Yong-Surk
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.11
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    • pp.101-109
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    • 2009
  • Generally, depth cache and pixel cache of 3D graphics are designed by using write-back scheme for efficient use of memory bandwidth. Also, there are write after read operations of same address or only write operations are occurred frequently in 3D graphics cache. If a cache miss is detected, an access to the external memory for write back operation and another access to the memory for handling the cache miss are operated simultaneously. So on frequent cache miss situations, as the memory access bandwidth limited, the access time of the external memory will be increased due to memory bottleneck problem. As a result, the total performance of the processor or the IP will be decreased, also the problem will increase peak power consumption. So in this paper, we proposed a novel early write back cache architecture so as to solve the problems issued above. The proposed architecture controls the point when to access the external memory as to copy the valid data block. And this architecture can improve the cache performance with same hit ratio and same capacity cache. As a result, the proposed architecture can solve the memory bottleneck problem by preventing intensive memory accesses. We have evaluated the new proposed architecture on 3D graphics z cache and pixel cache on a SoC environment where ARM11, 3D graphic accelerator and various IPs are embedded. The simulation results indicated that there were maximum 75% of performance increase when using various simulation vectors.

A Study on Knowledge Entity Extraction Method for Individual Stocks Based on Neural Tensor Network (뉴럴 텐서 네트워크 기반 주식 개별종목 지식개체명 추출 방법에 관한 연구)

  • Yang, Yunseok;Lee, Hyun Jun;Oh, Kyong Joo
    • Journal of Intelligence and Information Systems
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    • v.25 no.2
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    • pp.25-38
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    • 2019
  • Selecting high-quality information that meets the interests and needs of users among the overflowing contents is becoming more important as the generation continues. In the flood of information, efforts to reflect the intention of the user in the search result better are being tried, rather than recognizing the information request as a simple string. Also, large IT companies such as Google and Microsoft focus on developing knowledge-based technologies including search engines which provide users with satisfaction and convenience. Especially, the finance is one of the fields expected to have the usefulness and potential of text data analysis because it's constantly generating new information, and the earlier the information is, the more valuable it is. Automatic knowledge extraction can be effective in areas where information flow is vast, such as financial sector, and new information continues to emerge. However, there are several practical difficulties faced by automatic knowledge extraction. First, there are difficulties in making corpus from different fields with same algorithm, and it is difficult to extract good quality triple. Second, it becomes more difficult to produce labeled text data by people if the extent and scope of knowledge increases and patterns are constantly updated. Third, performance evaluation is difficult due to the characteristics of unsupervised learning. Finally, problem definition for automatic knowledge extraction is not easy because of ambiguous conceptual characteristics of knowledge. So, in order to overcome limits described above and improve the semantic performance of stock-related information searching, this study attempts to extract the knowledge entity by using neural tensor network and evaluate the performance of them. Different from other references, the purpose of this study is to extract knowledge entity which is related to individual stock items. Various but relatively simple data processing methods are applied in the presented model to solve the problems of previous researches and to enhance the effectiveness of the model. From these processes, this study has the following three significances. First, A practical and simple automatic knowledge extraction method that can be applied. Second, the possibility of performance evaluation is presented through simple problem definition. Finally, the expressiveness of the knowledge increased by generating input data on a sentence basis without complex morphological analysis. The results of the empirical analysis and objective performance evaluation method are also presented. The empirical study to confirm the usefulness of the presented model, experts' reports about individual 30 stocks which are top 30 items based on frequency of publication from May 30, 2017 to May 21, 2018 are used. the total number of reports are 5,600, and 3,074 reports, which accounts about 55% of the total, is designated as a training set, and other 45% of reports are designated as a testing set. Before constructing the model, all reports of a training set are classified by stocks, and their entities are extracted using named entity recognition tool which is the KKMA. for each stocks, top 100 entities based on appearance frequency are selected, and become vectorized using one-hot encoding. After that, by using neural tensor network, the same number of score functions as stocks are trained. Thus, if a new entity from a testing set appears, we can try to calculate the score by putting it into every single score function, and the stock of the function with the highest score is predicted as the related item with the entity. To evaluate presented models, we confirm prediction power and determining whether the score functions are well constructed by calculating hit ratio for all reports of testing set. As a result of the empirical study, the presented model shows 69.3% hit accuracy for testing set which consists of 2,526 reports. this hit ratio is meaningfully high despite of some constraints for conducting research. Looking at the prediction performance of the model for each stocks, only 3 stocks, which are LG ELECTRONICS, KiaMtr, and Mando, show extremely low performance than average. this result maybe due to the interference effect with other similar items and generation of new knowledge. In this paper, we propose a methodology to find out key entities or their combinations which are necessary to search related information in accordance with the user's investment intention. Graph data is generated by using only the named entity recognition tool and applied to the neural tensor network without learning corpus or word vectors for the field. From the empirical test, we confirm the effectiveness of the presented model as described above. However, there also exist some limits and things to complement. Representatively, the phenomenon that the model performance is especially bad for only some stocks shows the need for further researches. Finally, through the empirical study, we confirmed that the learning method presented in this study can be used for the purpose of matching the new text information semantically with the related stocks.

Influence of exterior joint effect on the inter-story pounding interaction of structures

  • Favvata, Maria J.;Karayannis, Chris G.;Liolios, Asterios A.
    • Structural Engineering and Mechanics
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    • v.33 no.2
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    • pp.113-136
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    • 2009
  • The seismic induced interaction between multistory structures with unequal story heights (inter-story pounding) is studied taking into account the local response of the exterior beam-column joints. Although several parameters that influence the structural pounding have been studied sofar, the role of the joints local inelastic behaviour has not been yet investigated in the literature as key parameter for the pounding problem. Moreover, the influence of the infill panels as an additional parameter for the local damage effect of the joints on the inter-story pounding phenomenon is examined. Thirty six interaction cases between a multistory frame structure and an adjacent shorter and stiffer structure are studied for two different seismic excitations. The results are focused: (a) on the local response of the critical external column of the multistory structure that suffers the hit from the slab of the adjacent shorter structure, and (b) on the local response of the exterior beam-column joints of the multistory structure. Results of this investigation demonstrate that the possible local inelastic response of the exterior joints may be in some cases beneficial for the seismic behaviour of the critical column that suffers the impact. However, in all the examined cases the developing demands for deformation of the exterior joints are substantially increased and severe damages can be observed due to the pounding effect. The presence of the masonry infill panels has also been proved as an important parameter for the response of the exterior beam-column joints and thus for the safety of the building. Nevertheless, in all the examined inter-story pounding cases the presence of the infills was not enough for the total amelioration of the excessive demands for shear and ductility of the column that suffers the impact.