• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.24-27
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• 2011

최근 스마트 폰 등 모바일 기기의 폭발적인 성장에 의해 내장 프로세서인 ARM 프로세서 기반 기기들이 활발히 개발되어 사용되고 있다. 이에 따라 상대적으로 저성능, 저 전력화에 치중하였던 내장 프로세서도 고성능화를 위한 고속 동작 및 멀티코어 프로세서를 개발하여 사용하게 되었으며, 메모리 동작 속도 역시 빠르게 발전하고 있다. 특히 모바일 기기 등에 사용 되는 저전력 메모리인 LPDDR2 소자 등의 개발에 따라 빠른 동작 속도를 가지도록 개발되고 있다. 그러나 시스템 온 칩(SoC, System on Chip) 형태로 제작되는 ARM 프로세서 기반의 SoC는 다양한 하드웨어 가속기 등을 함께 내장하고 있고, 저 전력화를 위한 버스 구조 등에 의하여 온 칩 버스의 속도 향상이 고성능 범용 시스템에 비하여 낮은 수준이다. 본 연구에서는 이러한 점을 고려하여, 프로세서 코어와 메모리 소자의 동작 속도 향상에 의하여 얻을 수 있는 성능 향상과, 상대적으로 낮은 버스 동작 속도에 의하여 저하되는 성능의 정도를 분석하고 이를 극복하기 위한 방안을 검토하였다.

• Electronics and Telecommunications Trends
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• v.36 no.4
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• pp.1-12
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• 2021

The competition to lead the next generation of mobile technologies, 6G, is underway while the deployment of 5G has not been implemented worldwide. ITU-R plans to develop technical requirements and standards after completing the 6G Vision by 2023. It can be considered too early to have a concrete view of the 6G core network architecture from this timeline. However, major stakeholders have started making their presence felt by publishing their views. From updated analysis on the technology and service trends proposed, we present a list of research directions on 6G core network from several perspectives: distribution of network functions to nearer edge locations; future fixed-mobile convergence, including low earth orbit satellites; highly-precise QoS guarantee; supporting an extremely wide variety of service requirements; AI-native automation and intelligence; and aligning with the evolution of radio access network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.203-208
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• 2017

Recently, the importance of DRAM is very significant in multicore processors which are widely used in computers, laptops, tablet PCs, and mobile devices. To keep up with this, both industry and academia have actively studied various types of future DRAMs. Therefore, accurate DRAM model is requisite when evaluating the multicore processor performance. In this paper, a multicore processor trace-driven simulator which can couple with the cycle-accurate DRAM simulator has been developed. Using SPEC 2000 benchmarks as input, the effect of cycle-accurate DDR3 model on the multicore processor performance has been evaluated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.251-256
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• 2017

Recently, multicore processor system is widely adopted not only in general purpose computers but also in embedded systems and mobile devices in order to improve performance. Since the power dissipation issue of multicore processor system is very significant, it must be estimated accurately in the early design stage. In this paper, a fast power analysis tool for a high performance multicore processor based on the trace-driven simulator has been developed. To achieve it, the power dissipation of each hardware unit per core are added. Using SPEC 2000 benchmarks as input, the trace-driven simulation has been performed to estimate the average power dissipation per instruction.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.6
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• pp.69-75
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• 2022

We propose energy-efficient scheduling considering real-time constraints and energy efficiency in smart mobile with heterogeneous multi-core structure. Recently, high-performance applications such as VR, AR, and 3D game require real-time and high-level processings. The big.LITTLE architecture is applied to smart mobiles devices for high performance and high energy efficiency. However, there is a problem that the energy saving effect is reduced because LITTLE cores are not properly utilized. This paper proposes a heterogeneous multi-core assignment technique that improves real-time performance and high energy efficiency with big.LITTLE architecture. Our proposed method optimizes the energy consumption and the execution time by predicting the actual task execution time using SVM (Support Vector Machine). Experiments on an off-the-shelf smartphone show that the proposed method reduces energy consumption while ensuring the similar execution time to legacy schemes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.9-22
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• 2006

When the legacy multicast routing protocols are adopted in If-based mobile core networks, there are some problems such as traffic injection from unnecessary sources, traffic overhead by group management and router performance degradation by large amount of multicast session information. In this paper, we propose a stateless multicast mechanism which has no need to maintain multicast information for session status and reduces redundant network overhead for maintaining multicast tree. In addition interworking with IGMPv3 gets rid of traffic from unnecessary sources which have no registration from receivers. The operations of essential components including a gateway node for interworking with the legacy Internet multicast network, a gateway node for transparency to radio access network and a intermediate node in mobile core networks, are definitely defined and the proposed communication architecture is completed. Finally we evaluate and approve the performance of the proposed architecture by means of well-designed network simulation.

• Journal of KIISE
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• v.44 no.3
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• pp.223-231
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• 2017

In this paper, we study the performance of recently popular multi-core systems in mobiles. Previous research on the multi-core performance usually focused on the desktop PC. However, there is enough scope to further analyze heterogeneous multi-core systems. Therefore, by extending homogeneous multi-core systems, we analyze the heterogeneous multi-core systems using Size Interval Task Allocation (SITA) for job allocation, and Shortest Remaining Processing Time (SRPT) scheduling, for each individual core. We propose a new computational method regarding the cutoff point, which is crucial in analyzing SITA, by calculating the sojourn time. This facilitate easy and accurate calculation of the sojourn time. We further confirm our analysis through the ESESC simulator that provides actual measurements.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.193-204
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• 2012

This paper specifies a low-cost global mobility management architecture and protocol procedure called LC-$GM^2$, which is based on Proxy Mobile IPv6. In LC-$GM^2$, mobility management is performed by the network entity. The benefit is the elimination of the wireless link data delivery tunnel overhead between a mobile node and the access router. To compare with the well-known Hierarchical Mobile IPv6 mobility management protocol and GPMIP, the location update, packet delivery, and total cost functions generated by a mobile node during its average domain residence time are formulated for each protocol based on Fluid-flow mobility model. Then, the impacts of various system parameters on the cost functions are analyzed. The analytical results indicate that the proposed global mobility management protocol can guarantee lower total costs.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.152-155
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• 2012

최근 스마트폰 및 타블릿PC 등 모바일 장치의 성능(쿼드코어)이 급격히 성장하고, 사용자의 증가, 무선 통신 환경(LTE, Wibro 등)의 발전으로 모바일 장치들을 연산 가능한 자원으로 고려하는 모바일 클라우드 연구가 이루어지고 있다. 그러나 자원 제공자인 모바일 장치의 자율적 연산 참여와 탈퇴가 가능하기 때문에 기존의 시스템들은 수행중인 연산이 중단되어 연산의 완료 시간이 지연되며, 시스템의 결함으로 이어지게 된다. 따라서 모바일 장치의 안정적인 연산 수행을 위한 안정적인 모바일 자원을 제공해야 한다. 본 논문에서는 신뢰적인 모바일 자원을 제공하기 위해 소셜 네트워크 정보를 이용하여 그룹화 함으로써 모바일 자원 관리를 제공한다

• Journal of Internet Computing and Services
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• v.22 no.3
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• pp.37-43
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• 2021

In this paper, we study how objects from front and back cameras can be recognized in real time in a mobile environment to segment regions of object pixels and synthesize them through image processing. To this work, we applied DeepLabV3 machine learning model to dual cameras provided by Apple's iOS. We also propose methods using Core Image and Core Graphics libraries from Apple for image synthesis and postprocessing. Furthermore, we improved CPU usage than previous works and compared the throughput rates and results of Depth and DeepLabV3. Finally, We also developed a camera application using these two methods.