• KIPS Transactions on Computer and Communication Systems
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• v.4 no.5
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• pp.153-160
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• 2015

The effectiveness of multicores depends on how well a scheduler can assign tasks onto the cores efficiently. In a heterogeneous multicore platform, the execution time of an application depends on which core it executes on. That is to say, the effectiveness of task assignment is one of the important components for a multicore systems' performance. This work proposes a load scheduling technique that analyzes execution time of each task by profiling. The profiling result provides a basic information to predict which task-to-core mapping is likely to provide the best performance. By using such information, the proposed technique is about 26% performance gain.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.33-36
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• 2014

최근 스마트폰이나 태블릿 PC 등의 모바일 디바이스가 상용화 되어감에 따라 그 안에서 핵심적인 처리기능을 담당하는 프로세서의 코어 수가 점차적으로 늘어나고 있다. 많은 수의 코어를 효율적으로 사용하기 위해 여러 가지 메커니즘이 구현되어 있으나, 단일 프로세스를 순차적으로 실행하는 경우 여전히 성능에서의 한계가 존재한다. 병렬화 되어 있지 않은 프로세스의 경우, Amdahl's Law[1]에 따르면 순차적으로 실행을 할 수 밖에 없는 부분이 존재하고, 이 부분은 하나의 코어에서만 실행되기 때문에 많은 연산 자원들이 낭비되는 현상이 발생한다. 본 논문은 다중 코어 환경에서 이러한 잉여자원을 효과적으로 사용하기 위해 Back-end Fusion 이라는 구조를 제안하여 프로세서의 성능 향상을 위한 연구를 진행하였다. Back-end Fusion 이란, 연산 처리를 담당하는 back-end 부분(execution unit, writeback 단계 등)을 필요에 따라 코어 간에 동적으로 재구성하여 성능을 향상시키는 메커니즘이다. 이 재구성된 프로세서의 back-end 를 효율적으로 사용하기 위해, 종속성과 로드 밸런스 등을 고려한 인스트럭션 분배 알고리즘을 함께 제안한다. Intel 사의 x86 Instruction Set Architecture(ISA)를 기반으로 한 시뮬레이터를 이용하여 Back-end Fusion 프로세서의 성능을 측정 해 본 결과 기존의 단일 코어 프로세서에 비해 평균 32.2%의 성능 향상을 확인할 수 있었다.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.116-120
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• 2008

Smart Camera provides intelligent vision functionalities which can interpret captured video, extract context-aware information and execute a necessary action in real-timeliness in addition to the functionality of network cameras which transmit the compressed acquired videos through networks. Intelligent vision algorithms demand tremendous computations so that real-time processing of computation of intelligent vision algorithms as well as compression and transmission of videos simultaneously is too much burden for a single CPU. Davinci processor of Texas Instruments is a popular ASSP(Application Specific Standard Product) which has dual core architecture of ARM core and DSP core and provides various I/O interfaces as well as networking interface and video acquiring interface necessary for developing digital video embedded applications. In this paper, we report the results of designing and implementing S/W for Davinci-based smart camera. We implement a face detection as an example of vision application and verify the implementation works well. In the future, for the development of a smart camera with more broad and real-time vision functionalities, it is necessary to study about more efficient vision application S/W architecture and optimization of vision algorithms on DSP core of Davichi processor.

• Smart Media Journal
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• v.9 no.3
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• pp.71-79
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• 2020

Mobile network is used by many users worldwide for diverse services, including phone-call, messaging and data transfer over the Internet. However, this network may experience massive damage if it is exposed to cyber-attacks or denial-of-service attacks via wireless communication interference. Because the mobile network is also used as an emergency network in cases of disaster, evaluation or verification for security and safety is necessary as an important nation-wide asset. However, it is not easy to analyze the mobile core network because it's built and serviced by private service providers, exclusively operated, and there is even no separate network for testing. Thus, in this paper, a virtual mobile network is built using OpenAirInterface, which is implemented based on 3GPP standards and provided as an open source software, and the structure and protocols of the core network are analyzed. In particular, the S1AP protocol messages captured on S1-MME, the interface between the base station eNodeB and the mobility manager MME, are analyzed to identify potential security threats by evaluating the effect of the messages sent from the user terminal UE to the mobile core network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.553-557
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• 2009

USS(Ubiquitous Smart Space) give services, that fit in with customer's goal, by cognizing various situations that happens in a space and cooperating autonomously objects or services in a space. In USS, U-Safety is a system that cognizes more exact situations with multiple sensors in USS, deals with this and take proper actions. When men reason on situations objectively, it is most ideal that image data among collected data with used various sensors in U-Safety. A senter collects a lot of image data from image input devices equipped in various points and work a multiple situation cognition and inference that are based on this. So, senters spend many resources for processing massive data. This paper proposes hierarchical image processing method that does the first situation cognization in image input devices, blocks only points that situation cognization possibility is high among a total image, and transfers to senters. It improves the efficiency of smooth situation cognization by reducing resources that a senter spends on image processing. So, it reduces proportion of image data in U-Safety.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.722-730
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• 2014

Due to the advance of hardware, various devices have mobility features, and many applications need the data transmission. In addition, it is essential for latest smartphones to utilize multi-cores and multi-threads because of the enhancement of Application Processor. Therefore, this paper analyzes the performance/power consumption according to transmission rate, the number of cores, and that of threads in the system that is supposed to conduct data transmission and processing simultaneously. Through the analysis, this paper provides a direction for the proper number of threads in terms of performance improvement and efficient power consumption.

• Smart Media Journal
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• v.3 no.4
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• pp.9-15
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• 2014

A virtual platform models a processor core and the peripheral devices constituting the SoC in software. Major companies utilize a variety of platforms for product development with optimal SW+SoC integrated system architecture design and IP reuse based Top-Down design flow using a virtual platform. In this paper, we propose a virtual platform based on OpenRISC, an open source RISC based core. The proposed virtual platform supports high speed emulation of approximately 20 MIPS using DBT (Dynamic Binary Translation).

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.457-459
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• 2000

최근 이동단말기나 PDA, 스마트폰과 같은 정보기기나 디지털 가전기기의 사용이 증대됨에 따라, ARM코어 시스템을 기반으로 하는 프로세서와 이를 운영하기 위한 소프트웨어 수요도 증가하고 있다. 본 논문은 프로세서를 운영하기 위한 소프트웨어 중에서 예외처리를 위한 일반적인 인터럽트 제어를 다룬다. ARM 시스템 상에서 임의의 주변 장치(타이머/카운터)에 의해 발생하는 인터럽트 처리 과정과 예외처리를 제어하기 위한 벡터 테이블을 구성하는 방법에 대해 분석한다. 그리고 인터럽트를 처리하는 인터럽트 코드부분과 벡터 테이블내의 인터럽트의 상호 연관성에 대해 논의한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.12
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• pp.1261-1266
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• 2014

Smart shipyard, all of the business of shipyard by using a mobile application, and the rapid spread of smart equipment, the overload of infrastructure due to a variety of mobile services is expected. Because macrocell and femtecell to reduce the overloading of existing infrastructure, additional core network devices have a problem, in this paper, the efficiency of resources than the communication over the existing infrastructure smart shipyard network to improve, to apply the D2D communication technology that can reduce the load on the infrastructure. The proposed routing path plan in accordance with the transfer method and the traffic type of network configuration and D2D equipment navigation and data for applying a smart shipyard. Whether to execute the function to overload traffic in the core network can send to the optimized path was confirmed by using the state transition diagram. Smart shipyard, by applying D2D communication allow efficient traffic handling than conventional communication method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4545-4553
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• 2014

Mobile GPU has led to the rapid development of smart phone graphic technology. Most recent smart phones are equipped with high-performance multi-core GPU. How a multi-core mobile GPU can be utilized efficiently will be a critical issue for improving the smart phone performance. On the other hand, most current research has focused on a single-core mobile GPU; studies of multi-core mobile GPU are rare. In this paper, the job scheduling patterns and the efficiency of multi-core mobile GPU are analyzed. In the profiling result, despite the higher number of GPU cores, the total processing time required for certain graphics applications were increased. In addition, when GPU is processing for 3D games, a substantial amount of overhead is caused by communication between not only the CPU and GPU, but also within the GPUs. These results confirmed that more active research for multi-core mobile GPU should be performed to optimize the present mobile GPUs.