• 한국멀티미디어학회논문지
• /
• 제24권8호
• /
• pp.1138-1148
• /
• 2021

In this study, we developed a 'shared-use mobility'-mounted local particulate matter monitoring terminal technology to measure the actual particulate matter concentration around me. As a mobile terminal device in the form of an IoT sensor platform, it is designed to be separated into a control module and a sensor module to minimize interference between sensors and to consider the optimal observation position of each sensor. As a result of the field test, it was confirmed that particulate matter was locally different depending on time and space even within the same area. In addition, it was confirmed that the concentration of particulate matter in the relevant section differed by up to 100 times compared to the surrounding area due to specific sources of particulate matter such as unpaved roads. In addition, we positively reviewed the applicability of the service in the real-time metaverse environment using this result. Through technological advancement and application of multiple shared-use mobilities, we expect to be able to provide new services for practical smart city air environment monitoring, such as localized particulate matter information, air pollution event information, and identification of causes of particulate matter.

• 한국데이타베이스학회:학술대회논문집
• /
• 한국데이타베이스학회 1999년도 춘계공동학술대회: 지식경영과 지식공학
• /
• pp.95-102
• /
• 1999

The web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. This Paper proposes an active web server which can facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such a goal, the active web server manages dependency relationships between shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefullness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System (ODBMS) called OBJECTSTORE using the C＋＋ programming language.

• Journal of Computing Science and Engineering
• /
• 제6권4호
• /
• pp.267-278
• /
• 2012

The state-of-the-art techniques in multicore timing analysis are limited to analyze multicores with shared instruction caches only. This paper proposes a uniform framework to analyze the worst-case performance for both shared instruction caches and data caches in a multicore platform. Our approach is based on a new concept called address flow graph, which can be used to model both instruction and data accesses for timing analysis. Our experiments, as a proof-of-concept study, indicate that the proposed approach can accurately compute the worst-case performance for real-time threads running on a dual-core processor with a shared L2 cache (either to store instructions or data).

• 정보처리학회논문지A
• /
• 제12A권7호
• /
• pp.605-612
• /
• 2005

스토리지 시스템의 성능과 용량이 증가됨에 따라서, 스토리지 시스템은 이제 다양한 사용자에 의해서 공유되어 사용되는 것이 일반화 되고있는 추세이다. 본 논문은 네트워크에서 널리 이용되는 토큰 버킷을 이용하여 공유 스토리지 시스템 상에서 각 사용자 원하는 스토리지 입출력성능을 확률적으로 보장하는 기법을 설계한다. 또한, 다양한 형태의 작업부하를 이용한 시뮬레이션을 통해서 제안된 알고리즘의 동작 및 성능을 검증한다.

• ETRI Journal
• /
• 제39권6호
• /
• pp.771-781
• /
• 2017

For efficient spectral utilization of satellite channels, a shared band transmission technique is introduced in this paper. A satellite transmits multiple received signals from a gateway and terminal in the common frequency band by superimposing the signals. To improve the power efficiency as well as the spectral efficiency, a travelling wave tube amplifier in the satellite should operate near the saturation level. This causes a nonlinear distortion of the superimposed transmit signal. Without mitigating this nonlinear effect, the self-interference cannot be properly cancelled and the desired signal cannot be demodulated. Therefore, an adaptive compensation scheme for nonlinearity is herein proposed with the proper operation scenario. It is shown through simulations that the proposed shared band transmission approach with nonlinear compensation and self-interference cancellation can achieve an acceptable system performance in nonlinear satellite channels.

• International Journal of Computer Science & Network Security
• /
• 제24권4호
• /
• pp.192-196
• /
• 2024

The memory coherence problem occurs while mapping shared virtual memory in a loosely coupled multiprocessors setup. Memory is considered coherent if a read operation provides same data written in the last write operation. The problem is addressed in the literature using different algorithms. The big question is on the correctness of such a distributed algorithm. Formal verification is the principal term for a group of techniques that routinely use an analysis that is established on mathematical transformations to conclude the rightness of hardware or software behavior in divergence to dynamic verification techniques. This paper uses UPPAAL model checker to model the dynamic distributed algorithm for shared virtual memory given by K.Li and P.Hudak. We analyse the mechanism to keep the coherence of memory in every read and write operation by using a dynamic distributed algorithm. Our results show that the dynamic distributed algorithm for shared virtual memory partially fulfils its functional requirements.

• 한국정보처리학회논문지
• /
• 제5권4호
• /
• pp.873-882
• /
• 1998

현재 병렬 데이타베이스 컴퓨터가 광범위하고 성공적으로 활용되고 있다. 이의 구조로는 주기억 장치와 디스크를 공유하지 않는 구조, 두가지를 모두 공유하는 구조, 디스크만을 공유하는 구조, 그리고 절충형 구조 등의 네가지 구조가 있다. 이 논문에서는 데이타베이스 컴퓨터 구조의 성능을 비교 분석하기 위하여 데이타베이스 컴퓨터 구조를 추상적인 모형으로 정의하고, 각각의 모형에 대하여 절충형 해쉬 조인 연산의 수행시간을 수식화한 성능식을 구하여 여러 가지 데이타베이스 컴퓨터 구조 모형의 수행시간을 비교 분석한다.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (C)
• /
• pp.483-487
• /
• 2006

단말의 이동성을 지원하는 Mobile IP에서 MN이 홈 네트워크에서 먼 곳으로 이동하는 경우, 매번 BU 시그널링을 하게 되면 Registration latency가 길어져, 이로 인해 불필요한 네트워크 트래픽을 유발한다. 따라서 계층을 두어 지역적인 이동성을 관리하는 MAP을 도입한 HMIPv6가 제안되었다. HMIPv6는 지역적인 LCoA와 외부에 노출되는 RCoA를 가진다. Mobile IP 환경에서의 BU메시지 취약성은 보안이슈가 되어왔으며, HMIPv6은 두 개의 CoA를 가지므로 보안위협은 배가된다. 본 논문에서는 Static Shared Key를 사용하여 HMIPv6의 LCoA BU 시그널링 관련 메시지의 인증을 제안함으로써 Mobile WG에서 제기된 BU 시그널링의 보안 취약성을 개선하였다.

• 한국컴퓨터정보학회논문지
• /
• 제3권2호
• /
• pp.169-175
• /
• 1998

ATM스위치에서 셀을 전송하기 위한 버퍼방식으로 HOL 블록킹을 방지하는 공유다중버퍼 방식이 있다. 그러나, 이러한 방식에서도 셀 손실이 발생하여 스위치의 성능을 저하시킨다. 따라서, 본 논문에서는 기존의 비충돌 공유 다중 버퍼 구조에서 발생하는 셀 손실을 방지하는 방안을 제안하였다. 셀 손실을 방지하는 방안으로 한 슬롯 타임동안에 손실되는 셀을 다음 슬롯 타임에 전송할 수 있도록 특정한 임시메모리에 저장할 수 있는 구조를 사용하였다. 이러한 구조를 시뮬레이션을 통해 성능평가를 한 결과 셀 손실율과 처리율면에서 기존의 시스템보다 우수함을 검증하였다.

• 디지털산업정보학회논문지
• /
• 제12권4호
• /
• pp.71-79
• /
• 2016

This study proposes a performance model of a shared bus multi-processor system and analyzes the effect of input/output types on system performance and overload of shared resources. This system performance model reflects the memory reference time in relation to the effect of input/output types on shared resources and the input/output processing time in relation to the input/output processor, disk buffer, and device standby places. In addition, it demonstrates the contribution of input/output types to system performance for comprehensive analysis of system performance. As the concept of workload in the probability theory and the presented model are utilized, the result of operating and analyzing the model in various conditions of processor capability, cache miss ratio, page fault ratio, disk buffer hit ratio (input/output processor and controller), memory access time, and input/output block size. A simulation is conducted to verify the analysis result.