• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.85-94
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• 2004

In this paper, a register allocation techlique that translates memory accesses to register accesses Is presented to enhance embedded software performance. In the proposed method, a source code is profiled to generate a memory trace. From the profiling results, target functions with high dynamic call counts are selected, and the proposed register allocation technique is applied only to the target functions to save the compilation time. The memory trace of the target functions is searched for the memory accesses that result in cycle count reduction when replaced by register accesses, and they are translated to register accesses by modifying the intermediate code and allocating Promotion registers. The experiments where the performance is measured in terms of the cycle count on MediaBench and DSPstone benchmark programs show that the proposed method increases the performance by 14% and 18% on the average for ARM and MCORE, respectively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.4
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• pp.919-928
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• 2018

Out-Of-Bounds (OOB) is one of the most powerful vulnerabilities in heap memory. The OOB vulnerability allows an attacker to exploit unauthorized access to confidential information by tricking the length of the array and reading or writing memory of that length. In this paper, we propose a method to automatically detect OOB vulnerabilities in heap memory using dynamic symbol execution and shadow memory table. First, a shadow memory table is constructed by hooking heap memory allocation and release function. Then, when a memory access occurs, it is judged whether OOB can occur by referencing the shadow memory, and a test case for causing a crash is automatically generated if there is a possibility of occurrence. Using the proposed method, if a weak block search is successful, it is possible to generate a test case that induces an OOB. In addition, unlike traditional dynamic symbol execution, exploitation of vulnerabilities is possible without setting clear target points.

• Journal of KIISE:Software and Applications
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• v.34 no.8
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• pp.708-720
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• 2007

Memory access errors are frequently occurred in computer programs written in C programming language [1,2]. Accordingly, a number of research works have suggested a wide variety of methods to detect such errors automatically. However, they have one or more of the following problems: inability to detect all memory errors, changing the memory allocation mechanism, and excessive performance overhead. To cope with these problems, in this paper we suggest a new and automated tool to detect dynamic memory access errors in C programs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.49-58
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• 2005

In this paper, we have proposed a secure dynamic ID allocation protocol using mutual authentication on the RFID tag. Currently, there are many security protocols focused on the low-price RFID tag. The conventional low-price tags have limitation of computing power and rewritability of memory. The proposed secure dynamic ID allocation protocol targets to the high-performance RFID tags which have more powerful performance than conventional low-price tag by allocating dynamic ID to RFID using mutual authentication based on symmetric encryption algorithm. This protocol can be used as a partial solution for ID tracing and forgery.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.4
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• pp.217-223
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• 2005

In this paper, we have proposed a secure dynamic ID allocation protocol using mutual authentication on the RFID tag. Currently, there are many security protocols focused on the low-price RFID tag. The conventional low-price tags have limitation of computing power and rewritability of memory. The proposed secure dynamic ID allocation protocol targets to the high-performance RFID tags which have more powerful performance than conventional low-price tag by allocating a dynamic ID to RFID using mutual authentication based on symmetric encryption algorithm. This protocol can be used as a partial solution for ID tracing and forgery.

• The KIPS Transactions:PartA
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• v.13A no.5 s.102
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• pp.387-398
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• 2006

In this paper, we propose a new page allocation scheme for flash memory file system. The proposed scheme allocates pages by exploiting the concept of Purity, which is defined as the fraction of blocks where valid Pages and invalid Pages are coexisted. The Pity determines the cost of block cleaning, that is, the portion of pages to be copied and blocks to be erased for block cleaning. To enhance the purity, the scheme classifies hot-modified data and cold-modified data and allocates them into different blocks. The hot/cold classification is based on both static properties such as attribute of data and dynamic properties such as the frequency of modifications. We have implemented the proposed scheme in YAFFS and evaluated its performance on the embedded board equipped with 400MHz XScale CPU, 64MB SDRAM, and 64MB NAND flash memory. Performance measurements have shown that the proposed scheme can reduce block cleaning time by up to 15.4 seconds with an average of 7.8 seconds compared to the typical YAFFS. Also, the enhancement becomes bigger as the utilization of flash memory increases.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.7
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• pp.708-712
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• 2008

Existing dynamic memory allocation schemes for general purpose operating system can not directly apply to the wireless sensor networks (WSNs). Because these schemes did not consider features of WSNs, they consume a lot of energy and waste the memory space caused by fragmentation. In this paper, we found features of WSNs applications and made the model which adapts these issues. Through this research, we suggest the slab allocator that reduces the execution time and the memory management space. Also, we evaluate the performance of our scheme by comparing to one of the previous systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.642-648
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• 2006

In this paper, I have proposed a secure dynamic ID allocation protocol using mutual authentication on the RFID tag. Currently, there are many security protocols focused on the low-price RFID tag. The conventional low-price tags have limitation of computing power and rewritability of memory. The proposed secure dynamic ID allocation protocol targets to the high-performance RFID tags which have more powerful performance than conventional low-price tag by allocating a dynamic ID to RFID using mutual authentication based on symmetric encryption algorithm. This protocol can be used as a partial solution for ID tracing and forgery.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1098-1105
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• 1999

The caches in distributed shared memory systems enhance the performance by reducing memory access latency and communication overhead, but they must solve the cache coherence problem. This paper proposes a new directory protocol to solve the cache coherence problem and to improve the system performance in distributed shared memory systems. To maintain the cache coherence of shared data, processors within a limited distance reduce the communication overhead by using a bit-vector like the full directory scheme. Processors over a limited distance store pointers in a directory pool. Since the bit-vector and the directory pool remove the unnecessary cache invalidations, the proposed scheme reduces the communication traffic and improves the system performance. The dynamic limited directory scheme reduces the communication traffic up to 66 percents compared with the limited directory scheme and the number of directory access up to 27 percents compared with the dynamic pointer allocation scheme.

• Journal of KIISE
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• v.44 no.5
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• pp.439-448
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• 2017

The workloads of large high-performance computing (HPC) scientific applications are steadily becoming "bursty" due to variable resource demands throughout their execution life-cycles. However, the over-provisioning of virtual resources for optimal performance during execution remains a key challenge in the scheduling of scientific HPC applications. While over-provisioning of virtual resources guarantees peak performance of scientific application in virtualized environments, it results in increased amounts of idle resources that are unavailable for use by other applications. Herein, we proposed a memory resource reconfiguration approach that allows the quick release of idle memory resources for new applications in OS-level virtualized systems, based on the applications resource-usage pattern profile data. We deployed a scientific workflow application in Docker, a light-weight OS-level virtualized system. In the proposed approach, memory allocation is fine-tuned to containers at each stage of the workflows execution life-cycle. Thus, overall memory resource utilization is improved.