• Title/Summary/Keyword: Memory allocation

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Design of a Rule-Based Solution Based on MFC for Inspection of the Hybrid Electronic Circuit Board (MFC 기반 하이브리드 전자보오드 검사를 위한 규칙기반 솔루션 설계)

  • Ko Yun-Seok
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.9
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    • pp.531-538
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    • 2005
  • This paper proposes an expert system which is able to enhance the accuracy and productivity by determining the test strategy based on heuristic rules for test of the hybrid electronic circuit board producted massively in production line. The test heuristic rules are obtained from test system designer, test experts and experimental results. The guarding method separating the tested device with circumference circuit of the device is adopted to enhance the accuracy of measurements in the test of analog devices. This guarding method can reduce the error occurring due to the voltage drop in both the signal input line and the measuring line by utilizing heuristic rules considering the device impedance and the parallel impedance. Also, PSA(Parallel Signature Analysis) technique Is applied for test of the digital devices and circuits. In the PSA technique, the real-time test of the high integrated device is possible by minimizing the test time forcing n bit output stream from the tested device to LFSR continuously. It is implemented in Visual C++ computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the interface with the electronic circuit database and the hardware direct control. Finally, the effectiveness of the builded expert system is proved by simulating the several faults occurring in the mounting process the electronic devices to the surface of PCB for a typical hybrid electronic board and by identifying the results.

A Real-Time Expert System for the High Reliability of Railway Electronic Interlocking System (철도 전자연동장치의 고신뢰화를 위한 실시간 전문가 시스템)

  • Go, Yun-Seok;Choe, In-Seon;Gwon, Yong-Hun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.11
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    • pp.1457-1463
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    • 1999
  • This paper develops an real-time expert system for the electronic interlocking system. it obtains the higher safety by determining the railway interlocking strategy in order to prevent trains from colliding, and derailing in the viewpoint of veteran expert, considering the situation of station in real-time. The expert system determines the real-time interlocking strategy by confirming the interlocking relationships among signal facilities based on the interlocking knowledge base from input information such as signal, points, and it is implemented as the rule-based system in order to represented accurately and effectively the interlocking relationships. Especially in case of emergency the function which determines the rational route coordinating with IIKBAG on the workstation is designed in order to minimize the spreading effect. It is implemented in C computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the build and interface of the station structure database. And, the validity of the built expert system is proved by simulating the diversity cases which may occur in the real system for the typical station model.

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A Study on the Analysis Method to API Wrapping that Difficult to Normalize in the Latest Version of Themida (최신 버전의 Themida가 보이는 정규화가 어려운 API 난독화 분석방안 연구)

  • Lee, Jae-hwi;Lee, Byung-hee;Cho, Sang-hyun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.29 no.6
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    • pp.1375-1382
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    • 2019
  • The latest version of commercial protector, Themida, has been updated, it is impossible to apply a normalized unpacking mechanism from previous studies by disable the use of a virtual memory allocation that provides initial data to be tracked. In addition, compared to the previous version, which had many values that determined during execution and easy to track dynamically, it is difficult to track dynamically due to values determined at the time of applying the protector. We will look at how the latest version of Themida make it difficult to normalize the API wrapping process by adopted techniques and examine the possibilities of applying the unpacking techniques to further develop an automated unpacking system.

A Study on the Efficiency of Join Operation On Stream Data Using Sliding Windows (스트림 데이터에서 슬라이딩 윈도우를 사용한 조인 연산의 효율에 관한 연구)

  • Yang, Young-Hyoo
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.2
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    • pp.149-157
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    • 2012
  • In this thesis, the problem of computing approximate answers to continuous sliding-window joins over data streams when the available memory may be insufficient to keep the entire join state. One approximation scenario is to provide a maximum subset of the result, with the objective of losing as few result tuples as possible. An alternative scenario is to provide a random sample of the join result, e.g., if the output of the join is being aggregated. It is shown formally that neither approximation can be addressed effectively for a sliding-window join of arbitrary input streams. Previous work has addressed only the maximum-subset problem, and has implicitly used a frequency based model of stream arrival. There exists a sampling problem for this model. More importantly, it is shown that a broad class of applications for which an age-based model of stream arrival is more appropriate, and both approximation scenarios under this new model are addressed. Finally, for the case of multiple joins being executed with an overall memory constraint, an algorithm for memory allocation across the join that optimizes a combined measure of approximation in all scenarios considered is provided.

Temporary Metadata Journaling Scheme to Improve Performance and Stability of a FAT Compatible File System (FAT 파일 시스템의 호환성을 유지하며 성능과 안정성을 향상시키는 메타데이터 저널링 기법의 설계)

  • Hyun, Choul-Seung;Choi, Jong-Moo;Lee, Dong-Hee;Noh, Sam-H.
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.3
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    • pp.191-198
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    • 2009
  • The FAT (File Allocation Table) compatible file system has been widely used in mobile devices and memory cards because of its data exchangeability among numerous platforms recognizing the FAT file system. By the way. modern embedded systems have tough demands for instant power failure recovery and superior performance for multimedia applications. The key issue is how to achieve the goals of superior write performance and instant booting capability while controlling compatibility issues. To achieve the goals while controlling compatibility issues. we devised a temporary meta-data journaling scheme for a FAT compatible file system. Benchmark results of the scheme implemented in a FAT compatible file system shows that it really improves write performance of the FAT file system by converting small random write for meta-data update to a large sequential write in journaling area. Also, it provides natural way to implement the instant booting capability. Nevertheless, the file system compatibility is temporarily compromised by the scheme because it stores updated meta-data in the temporary journaling area rather than to their original locations. However, the compatibility can be fully recovered at any time by journal-flushing that copies meta-data in journaling area to their original locations. Generally, the journal-flushing is done before un-mounting a memory card so that it can be used in other mobile devices which recognized FAT file system but not the temporary meta-data journaling scheme.

IRFP-tree: Intersection Rule Based FP-tree (IRFP-tree(Intersection Rule Based FP-tree): 메모리 효율성을 향상시키기 위해 교집합 규칙 기반의 패러다임을 적용한 FP-tree)

  • Lee, Jung-Hun
    • KIPS Transactions on Software and Data Engineering
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    • v.5 no.3
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    • pp.155-164
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    • 2016
  • For frequency pattern analysis of large databases, the new tree-based frequency pattern analysis algorithm which can compensate for the disadvantages of the Apriori method has been variously studied. In frequency pattern tree, the number of nodes is associated with memory allocation, but also affects memory resource consumption and processing speed of the growth. Therefore, reducing the number of nodes in the tree is very important in the frequency pattern mining. However, the absolute criteria which need to order the transaction items for construction frequency pattern tree has lowered the compression ratio of the tree nodes. But most of the frequency based tree construction methods adapted the absolute criteria. FP-tree is typically frequency pattern tree structure which is an extended prefix-tree structure for storing compressed frequent crucial information about frequent patterns. For construction the tree, all the frequent items in different transactions are sorted according to the absolute criteria, frequency descending order. CanTree also need to absolute criteria, canonical order, to construct the tree. In this paper, we proposed a novel frequency pattern tree construction method that does not use the absolute criteria, IRFP-tree algorithm. IRFP-tree(Intersection Rule based FP-tree). IRFP-tree is constituted with the new paradigm of the intersection rule without the use of the absolute criteria. It increased the compression ratio of the tree nodes, and reduced the tree construction time. Our method has the additional advantage that it provides incremental mining. The reported test result demonstrate the applicability and effectiveness of the proposed approach.

NEUROPSYCHOLOGICAL ASSESSMENT OF CHILDREN WITH ATTENTION DEFICIT/HYPERACTIVITY DISORDER (주의력결핍/과잉운동장애 아동의 신경심리학적 평가)

  • Shin, Min-Sup;Park, Suzanne
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.8 no.2
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    • pp.217-231
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    • 1997
  • This paper first reviewed the current neurological theories concerning the etiology of ADHD and secondly, examined results of studies that applied neuropsychological assessment methods in the examination of ADHD children both here in Korea and abroad. ADHD children were found to exhibit characteristic responses indicating deficits in vigilance, sustained attention, distractibility, allocation and regulation of attention in many assessments of attention, in addition to deficits in executive functioning, working and associative memory. Such neuropsychological assessment results suggest that in addition to dysfunction in the frontal lobe and the reticular activation system, dysfunction may exist in other neural pathways involving many areas of the brain. However, because a substantial number of neuropsychological assessment tools being employed in Korea for ADHD children had been developed abroad, a Korean standardization project involving ADHD and normal control children, in addition to other child psychiatric population pools must be conducted in order to obtain appropriate age norms and test validity, and in order to make possible a more accurate and precise comparison and interpretation in the assessment of ADHD children.

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An Efficient Wear-Leveling Algorithm for NAND Flash SSD with Multi-Channel and Multi-Way Architecture (멀티채널과 멀티웨이 구조의 NAND 플래시 SSD를 위한 효율적인 웨어레벨링 알고리듬)

  • Kim, Dong-Ho;Hwang, Sun-Young
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.7
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    • pp.425-432
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    • 2014
  • This paper proposes a wear-leveling algorithm that exploits the properties of SSD memories with multi-channel and multi-way architecture. When a write request arrives, the proposed algorithm classifies the stored data in DRAM buffer into hot or cold according to logical address access frequency, and performs data allocation to reduce deviation of block erase counts. It lowers the chance of increasing erase count by allocating cold data to blocks which have high erase count. Effectiveness of the proposed algorithm is verified by executing various applications on a multi-channel, multi-way SSD simulator. Experimental results show that differences in erase count among blocks is reduced by an average of 9.3%, and total erase count decreases by 4.6%, when compared to previous wear-leveling algorithm.

Dynamic Buffer Allocation Scheme for Caching in Realtime Multimedia Systems (실시간 멀티미디어 시스템에서의 캐슁을 위한 동적 버퍼 할당 기법)

  • Kwon, Jin-Baek;Yeom, Heon-Young;Lee, Kyung-Oh
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.4
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    • pp.420-430
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    • 2000
  • Several caching schemes for realtime multimedia systems have been proposed, but they focus only on increasing the hit ratio without providing any means to utilize the saved disk bandwidth due to cache hits. One of the most important metrics in multimedia systems is the number of clients that the systems can service simultaneously guaranteeing Quality of Service(QoS). Preemptive but Safe Interval Caching(PSIC) was proposed as a caching scheme which makes it possible to provide deterministic QoS.. However, it has no ability to adapt to the change of system environments since it has no mechanism to change the cache size. In this paper, we present a new caching scheme, Dynamic Interval Caching(DIC), which maximizes the performance, regardless of the change of system environments, providing hiccup-free service, by managing memory buffers dynamically. And it is demonstrated that DIC allocates buffer cache optimally, by comparing with PSIC through trace-driven simulations.

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On reducing the computing time of EFDC hydrodynamic model (EFDC 해수유동모형의 계산시간 효율화)

  • Jung, Tae-Sung;Choi, Jong-Hwa
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.14 no.2
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    • pp.121-129
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    • 2011
  • The EFDC model has been simplified to enhance the computing performance in hydrodynamic modeling. Water quality module and unnecessary conditional statements were deleted in subroutine list and memory allocation. The performance of the enhanced model (EFDC-E) was checked by applying EFDC and EFDC-E models to simulating the tidal flow in Mokpo coastal zone. Both two-dimensional models and threedimensional models have been applied and compared. Three-dimensional models showed better simulation results agreeing with observed currents than two-dimensional models. The simulation results of EFDC-E model gave good results agreeing with the simulation results of EFDC model and the observed data. The computing speed of EFDC-E model is improved 3 times faster than that of EFDC model in modeling hydrodynamic flow for real time of 3 days in both 2-dimensional modeling and 3-dimensional modeling. The EFDC-E model can be used widely for hydrodynamic modeling because of improved simulation speed.