• Transactions of the Society of Information Storage Systems
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• v.11 no.2
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• pp.36-40
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• 2015

The demand for flexible devices including solar cells, memories and batteries has increased rapidly over the past decades. In most flexible devices, polymer-based materials are used to enable the mechanical deformations such as bending or folding. Shape Memory Polymers (SMPs) is a high molecular compound polymer with flexibility and shape recovery characteristics. In this work, flexible shape memory device was fabricated by simply coating the conducting material, carbon nano-tube (CNT), on a shape memory polymer. Furthermore, durability of the device under various type of mechanical deformations was assessed. It is believed that the result of this work will aid in realization of a stretchable and wearable electronic device for practical applications.

• Language and Information
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• v.9 no.1
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• pp.69-92
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• 2005

Pattern recognition in cognitive agents is based on (i) the uninterpreted input data (e.g. parameter values) provided by the agent's hardware devices and (ii) and interpreted patterns (e.g. templates) provided by the agent's memory. Computationally, the task consists in finding the memory data corresponding best to the input data, for any given input. Once the best fitting memory data have been found, the input is recognized by applying to it the interpretation which happens to be stored with the memorized pattern. This paper presents a fast converging procedure which starts from a few initially recognized items and then analyzes the remainder of the input by systematically checking for items shown by memory to have been related to the initial items in previous encounters. In this way, known patterns are tried first, and only when they have been exhausted, an elementary exploration of the input is commenced. Efficiency is improved further by choosing the candidate to be tested next according to frequency.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.324-329
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• 2007

본 논문은 대부분의 Linux 운영체제에서 지원해 주는 System V의 IPC 중 하나인 Shared Memo의 성능을 개선하는 방안을 연구한다. Linux에서 사용되는 Shared Memory는 동일한 메모리 영역에 여러 개의 프로세스가 접근할 수 있도록 해 주는 기술이다. 본 논문에서는 Shared Memory의 큰 두 갈래 중 커널 단계에서 처리 되는 SVR 형식의 Shared Memory를 다룬다. 본 논문에서는 리눅스 운영체제의 공유 메모리 성능 개선 방안을 제안한다. 본 논문에서 제안하는 공유 메모리 성능 개선 방안은 듀얼 코어를 활용하여 기존의 단일 처리기 시스템에서보다 성능을 향상시킬 수 있도록 한다. 공유 메모리를 이용한 프로세스의 동작이 별개의 CPU에서 동작되도록 함으로써 성능 향상을 꾀한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.204-206
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• 2012

SMP(Symmetric Multi-Processing)는 Shared memory bus 를 사용함으로써 scalability 가 제한적이었다. 이런 SMP의 scalability 제한을 극복하기 위해 제안 된 것이 NUMA(Non Uniform Memory Access)이다. NUMA는 memory bus 를 CPU 별 local 하게 가지고 있어 자신이 가지는 memory 영역에 대해서는 다른 영역을 접근하는 것 보다 더 빠른 latency 를 가지는 구조이다. Local 한 memory 영역의 존재는 scalability를 높여 주었지만 서버 가상화 환경에서 VM을 동적으로 scheduling 을 하였을 때 VM의 page 가 실행되는 core 의 local 한 메모리 영역에 존재하지 않게 되면 remote access로 인해 local access보다 성능이 떨어진다. 이 논문에서는 서버 가상화 환경에서 최신 architecture인 AMD bulldozer에서 NUMA affinity가 위반되었을 때 발생하는 성능 저하와 어떤 상황에서 이런 NUMA affinity가 위반되어도 성능저하가 없는지 연구하였다.

• Journal of information and communication convergence engineering
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• v.22 no.2
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• pp.139-144
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• 2024

In this study, four types of fall detection systems - designed with YOLOPose, principal component analysis (PCA), convolutional neural network (CNN), and long short-term memory (LSTM) architectures - were developed and compared in the detection of everyday falls. The experimental dataset encompassed seven types of activities: walking, lying, jumping, jumping in activities of daily living, falling backward, falling forward, and falling sideways. Keypoints extracted from YOLOPose were entered into the following architectures: RAW-LSTM, PCA-LSTM, RAW-PCA-LSTM, and PCA-CNN-LSTM. For the PCA architectures, the reduced input size stemming from a dimensionality reduction enhanced the operational efficiency in terms of computational time and memory at the cost of decreased accuracy. In contrast, the addition of a CNN resulted in higher complexity and lower accuracy. The RAW-LSTM architecture, which did not include either PCA or CNN, had the least number of parameters, which resulted in the best computational time and memory while also achieving the highest accuracy.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.199-201
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• 2024

많은 양의 데이터 처리를 요구하는 오늘날, 메모리 입/출력 없이 데이터를 처리할 수 있는 Processing-In Memory가 많은 관심을 받고 있다. Processing-In Memory는 소프트웨어 라이브러리를 통해 접근할 수 있는데, 적절히 구현되지 않은 라이브러리는 공격 대상이 된다. 본 논문에서는 Processing-In Memory 소프트웨어 라이브러리에 존재하는 시간적 접근 취약점을 분석하고 그에 대한 완화기법을 제시한다.

• Korean Journal of Cognitive Science
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• v.17 no.1
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• pp.15-27
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• 2006

The effects of the number of Hangul syllable, the nunber/location of batchim in a Hangul word, and compound/noncompound Hangul word on memory span were examined. The results were that (1) the more syllables a word had, the lower us memory span was, (2) the more batchims a two-syllable word had, the lower its memory span was (Korean batchim effect on memory span), (3) noncompound word had higher memory span than compound word. The reading speed of above mentioned words was measured and the results were that (1) the more syllables a word had, the slower its reading speed was, (2) but the reading speed of a two-syllable word was forest when it had a batchim on second syllable than when it had no batchim or had a batchim on first syllable or batchims on both syllables (Korean ending batchim effect on reading speed), (3) noncompound word was read faster thu compound word. Korean ending batchim effect on reading speed was not compatible with the explanation by articulatory loop bur compatible with the explanation by visual cache where the orthographic information was represented. The results suggest that memory span was influenced nor only by phonological information but also by orthographic information.

• Journal of the Korea Society of Computer and Information
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• v.15 no.3
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• pp.1-10
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• 2010

As processor platforms are continuously moving toward wireless mobile systems, embedded mobile processors are expected to perform more and more powerful, and therefore the development of an efficient power management algorithm for these battery-operated mobile and handheld systems has become a critical challenge. It is well known that a memory system is a main performance limiter in the processor point of view. Although many DVFS studies have been considered for the efficient utilization of limited battery resources, recent works do not explicitly show the interaction between the processor and the memory. In this research, to properly reflect short/long-term memory access patterns of the embedded workloads in wireless mobile processors, we propose a memory buffer utilization as a new index of DVFS level prediction. The simulation results show that our solution provides 5.86% energy saving compared to the existing DVFS policy in case of memory intensive applications, and it provides 3.60% energy saving on average.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.226-232
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• 2023

As a potential alternative to flash memory, HfO₂/Al₂O₃ stacks appear to be a viable option as charge capture layers in charge trapping memories. The paper undertakes a review of HfO₂/Al₂O₃ stacks as charge trapping layers, with a focus on comparing the number, thickness, and post-deposition heat treatment and γ-ray and white x-ray treatment of such stacks. Compared to a single HfO₂ layer, the memory window of the 5-layered stack increased by 152.4% after O₂ annealing at ±12 V. The memory window enlarged with the increase in number of layers in the stack and the increase in the Al/Hf content in the stack. Furthermore, our comparison of the treatment of HfO₂/Al₂O₃ stacks with varying annealing temperatures revealed that an increased annealing temperature resulted in a wider storage window. The samples treated with O₂ and subjected to various γ radiation intensities displayed superior resistance. and the memory window increased to 12.6 V at ±16 V for 100 kGy radiation intensity compared to the untreated samples. It has also been established that increasing doses of white x-rays induced a greater number of deep defects. The optimization of stacking layers along with post-deposition treatment condition can play significant role in extending the memory window.

• Journal of Information Technology Applications and Management
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• v.11 no.1
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• pp.189-200
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• 2004

Recently Flash Memory which is small and low-powered is widely used as a storage of embedded system, because an embedded system requests portability and a fast response. To resolve a difference of access time between a storage and RAM, Linux is using disk caching which copies a part of file on disk into RAM. It is not also an exception on embedded system. A READ access-time of flash memory is similar to RAMs. So, when a process on an embedded system reads data, it is similar to the time to access cached data in RAM and to access directly data on a flash memory. On the embedded system using limited memory, using a disk cache is that wastes much time and memory spaces to manage it and can not reflects the characteristic of a flash memory. This paper proposes the regular file access of limited using a page cache in the file system based on a flash memory and reflects the characteristic of a flash memory. The proposed algorithm minimizes power consumption because access numbers of the RAM are reduced and doesn't waste a memory space because it accesses directly to a flash memory Therefore, the performance improvement of the system applying the proposed algorithm is expected.