• International journal of advanced smart convergence
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• 제6권1호
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• pp.26-31
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• 2017

When mobile navigator device accesses data randomly, the cache memory performance is rapidly deteriorated due to low memory access locality. For instance, GPS (General Positioning System) of navigator program for automobiles or drones, that are currently in common use, uses data from 32 satellites and computes current position of a receiver. This computation of positioning is the major part of GPS which accounts more than 50% computation in the program. In this computation task, the satellite signals are received in real time and stored in buffer memories. At this task, since necessary data cannot be sequentially stored, the data is read and used at random. This data accessing patterns are generated randomly, thus, memory system performance is worse by low data locality. As a result, it is difficult to process data in real time due to low data localization. Improving the low memory access locality inherited on the algorithms of conventional communication applications requires a certain optimization technique to solve this problem. In this study, we try to do optimizations with data and memory to improve the locality problem. In experiment, we show that our case study can improve processing speed of core computation and improve our overall system performance by 14%.

• 전자공학회논문지S
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• 제34S권10호
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• pp.132-140
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• 1997

This paper proposes systolic array architectures for compuataion of the 1-D and 2-D discrete wavelet transform (DWT). The proposed systolic array for compuataion of the 1-D DWT consists of L processing element (PE) arrays, where the PE array denotes the systolic array for computation of the one level DWT. The proposed PE array computes only the product terms that are required for further computation and the outputs of low and high frequency filters are computed in alternate clock cycles. Therefore, the proposed architecuter can compute the low and high frequency outputs using a single architecture. The proposed systolic array for computation of the 2-D DWT consists of two systolic array architectures for comutation of the 1-D DWT and memory unit. The required time and hardware cost of the proposed systolic arrays are comparable to those of the conventional architectures. However, the conventional architectures need extra processing units whereas the proposed architectures fo not. The proposed architectures can be applied to subband decomposition by simply changing the filter coefficients.

• 한국통신학회논문지
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• 제31권6C호
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• pp.603-613
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• 2006

저전력 설계는 시스템의 소모전력을 줄임으로써 에너지 절약과 함께 휴대용 장치의 배터리 수명을 극대화시킴에 있어 직면한 가장 중요한 문제이다. 본 논문에서는 개량형 CSHM을 이용하여 저전력 DCT 구조를 제안하였다. 제안된 구조는 Computation Sharing Multiplication 연산 과정 중 불필요한 비트에 대한 연산을 수행하지 않는다. 실험 결과, 기존의 DCT 알고리즘과 동일한 연산 결과를 보이면서도 최대 약 9%의 소모전력이 감소하였다. 따라서 제안된 저전력 DCT 구조는 저전력 및 고성능으로 DCT 알고리즘을 처리해야하는 휴대용 멀티미디어 시스템에 적용이 가능하다.

• ETRI Journal
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• 제32권4호
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• pp.622-625
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• 2010

In this letter, we assess the scalability of a path computation flooding (PCF) approach to compute optimal end-to-end inter-domain paths in a path computation element-based multi-domain network. PCF yields a drastically reduced network blocking probability compared to a blind per-domain path computation but introduces significant network control overhead and path computation complexity. In view of this, we introduce and compare an alternative low overhead PCF (LoPCF) solution. From the obtained results, LoPCF leads to similar blocking probabilities to PCF while exhibiting around 50% path computation complexity and network control overhead reduction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4347-4366
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• 2015

Distinguished with traditional strategies which offload an application's computation to a single server, parallel computation offloading can promote the performance by simultaneously delivering the computation to multiple computing resources around the mobile terminal. However, due to the variability of communication and computation environments, static application component multi-partitioning algorithms are difficult to maintain the optimality of their solutions in time-varying scenarios, whereas, over-frequent algorithm executions triggered by changes of environments may bring excessive algorithm costs. To this end, an adaptive application component mapping algorithm for parallel computation offloading in variable environments is proposed in this paper, which aims at minimizing computation costs and inter-resource communication costs. It can provide the terminal a suitable solution for the current environment with a low incremental algorithm cost. We represent the application component multi-partitioning problem as a graph mapping model, then convert it into a pathfinding problem. A genetic algorithm enhanced by an elite-based immigrants mechanism is designed to obtain the solution adaptively, which can dynamically adjust the precision of the solution and boost the searching speed as transmission and processing speeds change. Simulation results demonstrate that our algorithm can promote the performance efficiently, and it is superior to the traditional approaches under variable environments to a large extent.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1316-1318
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• 2009

Nonideality of LED lens and diffuser as well as crosstalk between backlights should be compensated because they have large effects on image qualities. The computation complexities of conventional compensations are greatly increased as resolution becomes higher. The block based compensation is proposed to alleviate the computation complexity considering backlight profiles and image pixel characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.12-15
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• 2005

The subject of this research is not only to examine effects on electrical wiring that voltage drops make in low voltage load facilities found in apartments, buildings street lightings, factories, and etc, but also to discuss the voltage drops computation program on distributed random loads to optimize their safety and economy.

• 한국정보전자통신기술학회논문지
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• 제13권6호
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• pp.568-574
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• 2020

본 논문에서는 영상처리에 사용되는 Canny edge 검출 알고리즘 중 가장 높은 연산 복잡도를 가진 제곱근 연산 횟수를 감소시키는 방법을 제안한다. 제안하는 방법은 기울기 벡터 연산 과정에 사용되는 제곱근 연산을 이용할 때 일부 픽셀에 특정한 규칙을 사용해 홀을 만들어 제곱근 연산을 직접 하지 않고 주변 픽셀들의 연속성을 이용하여 기울기 벡터를 계산하여 연산 횟수를 감소시킨다. 다양한 테스트 이미지를 이용해 실험한 결과 홀이 1개인 경우 약 97%, 홀을 증가시키면 각각 약 94%, 90%, 88%의 일치율을 보였고, 홀이 1개인 경우에는 0.2ms의 연산시간이 감소되었고, 홀을 증가시키면 각각 약 0.398ms 0.6ms, 0.8ms의 연산시간이 감소되었다. 이를 바탕으로 hole이 2개인 경우 높은 정확도와 연산 수 절감을 통해 저전력 임베디드 비전 시스템을 구현할 수 있을 것으로 기대한다.

• 대한전기학회논문지
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• 제45권2호
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• pp.265-272
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• 1996

In this paper, attitude computation algorithm for a strap down ARS(Attitude Reference System)of an underwater vehicle has been studied. Attitude errors o the ARS using low-level gyroscopes tend to increase with time due to gyroscope errors. To cope with this problem, a mixing algorithm of accelerometer aided attitude computation has been developed. The algorithm can successfully bound the error increase for cruising motion, but it gives instantaneously large errors when a vehicle maneuvers. To improve the performance in case of vehicle's maneuver, a new attitude computation mixing algorithm complying state of vehicle and to manage the adjustment of the gains which are invariant in the existing algorithm. In addition, a gain scheduling method is applied to fuzzy inference composition process for real-time computation. Monte Carlo simulation results show that the proposed algorithm provides better performance than the existing algorithm.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.419-421
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• 2018

Cloud vehicular networks are a promising paradigm to improve vehicular through distributing computation tasks between remote clouds and local vehicular terminals. Software-Defined Network(SDN) can bring advantages to Intelligent Transportation System(ITS) through its ability to provide flexibility and programmability through a logically centralized controlled cluster that has a full comprehension of view of the network. However, as the SDN paradigm is currently studied in vehicular ad hoc networks(VANETs), adapting it to work on cloud-based vehicular network requires some changes to address particular computation features such as task computation of applications of cloud-based vehicular networks. There has been initial work on briging SDN concepts to vehicular networks to reduce the latency by using the fog computing technology, but most of these studies do not directly tackle the issue of task computation. This paper proposes a Software-Defined Cloud-based vehicular Network called SDCVN framework. In this framework, we study the effectiveness of task computation of applications of cloud-based vehicular networks with vehicular cloud and roadside edge cloud. Considering the edge cloud service migration due to the vehicle mobility, we present an efficient roadside cloud based controller entity scheme where the tasks are adaptively computed through vehicular cloud mode or roadside computing predictive trajectory decision mode. Simulation results show that our proposal demonstrates a stable and low route setup time in case of installing the forwarding rules of the routing applications because the source node needs to contact the controller once to setup the route.