DAMA방식 위성통신에서 Hysteresis특성에 따른 Access 제어채널의 과부하 측정 및 제어기법

최형석,Choi, Hyung-Seok 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.7B

본 논문에서는 위성통신 링크를 이용한 DAMA방식 호 서비스를 할 때 일부 제어채널의 고장으로 인한 과부하 발생시 이에 대한 측정 방안과 관리 기법을 제안하고 그 성능을 분석한다. 제안하는 기법은 망제어기에서 호 접속제어를 위한 Access 채널의 부하를 측정하여 과부하 상태를 검출하고 이를 DAMA망의 단말들에 고지하여 과부하제어를 수행함으로써 부하 상태에서 시스템의 성능과 안정성을 향상시킨다. 또한, 너무 잦은 과부하 상태 변경이 이루어지지 않도록 상태변경을 함에 있어 Hysteresis 특성을 반영하였다. 분석결과 과부하로 인한 호설정 지연의 과도한 증가 및 호성공율의 급격한 저하를 방지할 수 있으며, 잦은 상태 변경을 방지함으로써 망의 안정성을 높여줌을 알 수 있었다. This paper proposes the measurement scheme for network overload and the control technique in case of breaking several control channels when we support the call services of DAMA through communication satellite(GEO, Geostationary Earth Orbit). And its performance is analyzed. The proposed schemes measure the overload of access control channel of a network controller to control the call connections, detect the level of network overload, notify the terminals of DAMA network of the state, and excute overload control. As a result, it improves the system performance and the network stability at overload state. Moreover hysteresis is applied to the change of overload state for the restriction of the frequent state shifts. The results show that the proposed algorithm prevents excessive increment of call-setup delay and too much lowering of call success rate, and improves the network stability.

HIPERLAN/2를 위한 적응적 랜덤 액세스 알고리즘

송영금,이정규,Song Young-keum,Lee Jong-kyu 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.5B

본 논문에서는 HIPERLAN/2(HIgh PErformance Radio Local Area Network type 2)의 랜덤 액세스 과정에서 채널 환경을 고려함으로 처리 성능을 높이고 전송 지연을 개선한 적응적 랜덤 액세스 기법(ARAH : Adaptive Random Access algorithm for HIPERLAN/2)을 제안하고 기존 방식에 비해 성능이 향상됨을 검증하였다. 본 논문에서는 HIPERLAN/2에서 채널의 상태에 따라 OFDM(Orthogonal frequency Division Multiplexing) modulation scheme을 기반으로 제공하는 7가지 PHY(Physical) mode를 Good 그룹과 Bad 그룹으로 양분하고, Good 그룹에 속하는 단말들에게 랜덤 액세스 과정에서 우선순위를 갖게 함으로써 처리율을 높이도록 하는 방식을 취하고 있다. ARAH 방식에 대하여 성능을 평가한 결과, 처리율과 전송 지연에 대해 성능이 향상됨을 보이고 있다. In this paper, we proposed and evaluated ARAH(Adaptive Random Access algorithm for HIPERLAN/2) to improve system performance. In this paper, HIPERLAN/2 uses OFDM(Orthogonal Frequency Division Multiplexing) modulation scheme to select appropriate PHY mode by Radio Channel Quality, Proposed the ARAH scheme uses these 7 PHY mode when mobile terminal determines the RCH(Random CHannel) number for random access. In this paper, these 7 PHY mode divided into two group, good and bad, and will be given high priority to mobile terminals which are in a good group. In the result of performance evaluation. ARAH algorithm, ARAH has a better performance of throughput and delay than existing algorithm.

Artificial Collision-Based Dynamic Slot Assignment for In-Band Control Networks

Jong-Kwan Lee,Kyu-Man Lee,Hong-Jun Noh,Jae-Sung Lim IEEE 2014 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.13 No.11

<P>In this paper, we propose a novel dynamic slot-assignment scheme using artificial collisions called artificial collision-based dynamic slot assignment (AC-DSA) for multi-hop networks, which is based on the in-band control mechanism. In-band control-based networks have no exclusively reserved slots for newly arrived nodes; thus, the throughput can be improved compared with that of the out-of-band control-based networks. In in-band control based networks, a newly arrived node can use idle slots to transmit its control packet to request a slot assignment. However, if no idle slots are available, the node cannot transmit its control packet even though it has a higher priority than the existing nodes in the network, because a newly arrived node has to wait until idle slots are available in conventional schemes. To address this issue, AC-DSA uses the duration information of artificial packet collisions as a control message for slot assignment, which enables nodes with high priority to deprive a non-idle slot of nodes with low priority to guarantee quality of service requirements when no idle slots are available. We formulate an analytical model for the proposed slot-assignment scheme and compare it with the conventional one. Further, we demonstrate the feasibility and efficiency of the AC-DSA during high-traffic conditions considering the capture effect.</P>

Collaborative design by sharing multiple-level encryption files

Kim, Ki Chang,Yoo, Sang Bong Sage Publications Ltd. 2014 Concurrent Engineering Vol.22 No.1

<P>A design file can grow in size as the complexity of the target object increases. A large design file can reside in a large parallel computing system, such as a cloud computing system, and many designers can work concurrently on the same file. In such a case, it is obvious that we need some kind of protection mechanism allowing each user to access only the area of the file they are permitted to access. We take the encryption approach to ensure the safety of a file, even in the public domain such as on a cloud system, and in this article, we suggest a multi-level encryption scheme allowing each user to access a file only at the level the user has legitimate right to access. Each level of the file is encrypted with a different key, and the keys are shown only to those who have the right access permission. This article describes the necessary file format used to achieve this goal and discusses the file manipulation functions used to handle this new file format.</P>

Traffic Generation Rate Control of Wireless Sensor and Actuator Networks

IEEE 2015 IEEE COMMUNICATIONS LETTERS Vol.19 No.5

<P>The traffic generation rate of the network used for cyber-physical systems is a crucial design parameter since it directly affects the stability of physical systems and the congestion level of communication systems. In this paper, we propose a novel modeling framework of the general wireless sensor and actuator networks of cyber-physical systems where the sensor-controller and controller-actuator sides communicate over a lossy network. The performance model is then used to derive the optimal traffic generation rate of sensors and controllers for minimizing the maximum outage probability of the stability constraint of the control systems while guaranteeing a schedulability constraint. The resulting problem is a non-linear optimization problem which allows to obtain the global optimum. An efficient approximation converts the proposed optimization problem into a linear programming problem. One interesting finding is that the optimal solution assigns higher traffic generate rate on the controller-actuator link compared to the one of the sensor-controller link since the actuating-link is more critical to guarantee the stability of the control systems.</P>

Cooperative MAC Protocol Using Active Relays for Multi-Rate WLANs

Chang-Yeong Oh,Tae-Jin Lee,최선웅 한국통신학회 2011 Journal of communications and networks Vol.13 No.5

Cooperative communications using relays in wireless networks have similar effects of multiple-input and multiple-output without the need of multiple antennas at each node. To implement cooperation into a system, efficient protocols are desired. In IEEE 802.11 families such as a/b/g, mobile stations can automatically adjust transmission rates according to channel conditions. However throughput performance degradation is observed by low-rate stations in multi-rate circumstances resulting in so-called performance anomaly. In this paper, we propose active relay-based cooperative medium access control (AR-CMAC) protocol, in which active relays desiring to transmit their own data for cooperation participate in relaying, and it is designed to increase throughput as a solution to performance anomaly. We have analyzed the performance of the simplified AR-CMAC using an embeddedMarkov chain model to demonstrate the gain of AR-CMAC and to verify it with our simulations. Simulations in an infrastructure network with an IEEE 802.11b/g access point show noticeable improvement than the legacy schemes.

Cooperative MAC Protocol Using Active Relays for Multi-Rate WLANs

Oh, Chang-Yeong,Lee, Tae-Jin The Korea Institute of Information and Commucation 2011 Journal of communications and networks Vol.13 No.5

Cooperative communications using relays in wireless networks have similar effects of multiple-input and multiple-output without the need of multiple antennas at each node. To implement cooperation into a system, efficient protocols are desired. In IEEE 802.11 families such as a/b/g, mobile stations can automatically adjust transmission rates according to channel conditions. However throughput performance degradation is observed by low-rate stations in multi-rate circumstances resulting in so-called performance anomaly. In this paper, we propose active relay-based cooperative medium access control (AR-CMAC) protocol, in which active relays desiring to transmit their own data for cooperation participate in relaying, and it is designed to increase throughput as a solution to performance anomaly. We have analyzed the performance of the simplified AR-CMAC using an embedded Markov chain model to demonstrate the gain of AR-CMAC and to verify it with our simulations. Simulations in an infrastructure network with an IEEE 802.11b/g access point show noticeable improvement than the legacy schemes.

센서 네트워크에서 효과적인 트래픽 제어 방법과 에너지 효율성을 고려한 Media Access 기법

민병웅,김동일,Min Byung-Ung,Kim Dong-Il 한국정보통신학회 2006 한국정보통신학회논문지 Vol.10 No.6

센서를 통해 수집된 데이터는 모든 정보를 취합하는 기지국으로 전송되게 된다. 센서들은 데이터를 전송하면서 지속적으로 주변 환경에 대한 데이터를 수집하여야 하기 때문에 에너지 소모가 크다. 본 논문에서는 수집된 데이터가 효율적으로 전송되어 트래픽 혼잡을 피하면서 에너지 효율성을 고려하는 기법을 제안한다. 트래픽이 증가하거나 감소할 때 전송률을 제어함으로써 Traffic 혼잡을 피하고, 기본적인 CSMA(Carrier Sense Multiple Access) 프로토콜에 최적의 옵션을 설정하여 각 센서에서 에너지 소모를 최소화는 기법이다. 시뮬레이션을 통해 최적의 CSMA 옵션과 제안된 트래픽 제어 기법을 적용하여 성능을 분석하고, 에너지 효율성과 효과적인 트래픽 제어 방법을 제시한다. Data collected by sensors in field are transmitted to the base station gathering all of data. Because sensors have to gather data in surroundings and periodically transmit data to the base station, it makes energy consumed much. In this paper, we mose the scheme that is to avoid traffic congestion with achievement of energy efficiency, so collected data is transmitted efficiently. This is to adjust transmission rate differently in case of increasing or decreasing traffic and minimize the energy consumption with setting ideal options up basic CSMA(Carrier Sense Multiple Access) protocol in each sensor. Through the simulation, we find the ideal CSMA options and apply the proposed scheme of traffic control mechanism to them and analyze them, then show energy efficiency and effective traffic control mechanism.

수중 음향 센서 네트워크에서 비직교 다중 접속을 위한 다차원 노드 페어링 기법

천진용(Jinyong Cheon),조호신(Ho-Shin Cho) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.6

최근 해양 수중 산업의 발전으로 수중 센서 네트워크(UWASN: Underwater Acoustic Sensor Network)에 대한 관심이 증대되고 있다. 수중 센서 네트워크를 효율적으로 운용하기 위해서는 노드 간 전송 충돌을 방지하고 통신자원을 효율적으로 공유할 수 있는 매체 접속 제어(MAC: Medium Access Control) 프로토콜을 적용하는 것이 매우 중요하다. 하지만 수중 채널은 지상 무선 통신 환경과 달리 좁은 대역폭, 긴 전파 지연 시간, 낮은 전송률 등의 특성을 가지므로 지상 환경에서 개발된 비직교 다중 접속(NOMA: Non Orthogonal Multiple Access)의 노드 페어링 기법을 그대로 적용할 수 없다. 따라서 본 논문에서는 수중 채널의 특수성을 고려한 수중 음향 센서 네트워크에서의 비직교 다중 접속 다차원 노드 페어링 기법을 제안한다. 기존의 기법들은 노드 페어링 시 채널 품질만을 고려하였다. 기존 기법과 달리 제안 기법에서는 채널 품질 뿐 아니라 노드 간 공평성, 트래픽 부하, 패킷의 나이를 추가로 고려하여 최적의 노드 쌍(node-pair)을 찾는다. 추가적으로, 송신 노드는 실제 경로 손실 대신 노드 쌍 가능 노드 목록(PNL: Pairable Nodes List)을 활용함으로써 노드 페어링 시의 계산 복잡도를 줄인다. 시뮬레이션 결과에 따르면 공평성 요소까지 고려한 제안 기법이 기존 기법 대비 최대 23.8% 전송률 증가, 28% 지연 시간 감소, 공평성은 최대 5.7% 향상됨을 확인할 수 있었다. The interest in underwater acoustic sensor networks (UWASNs), along with the rapid development of underwater industries, has increased. To operate UWASNs efficiently, it is important to adopt well-designed medium access control (MAC) protocols that prevent collisions and allow the sharing of resources between nodes efficiently. On the other hand, underwater channels suffer from a narrow bandwidth, long propagation delay, and low data rate, so existing terrestrial node pairing schemes for non orthogonal multiple access (NOMA) cannot be applied directly to underwater environments. Therefore, a multi-dimensional node pairing scheme is proposed to consider the unique underwater channel in UWASNs. Conventional NOMA schemes have considered the channel quality only in node pairing. Unlike previous schemes, the proposed scheme considers the channel gain and many other features, such as node fairness, traffic load, and the age of data packets to find the best node-pair. In addition, the sender employs a list of candidates for node-pairs rather than path loss to reduce the computational complexity. The simulation results showed that the proposed scheme outperforms the conventional scheme by considering the fairness factor with 23.8% increases in throughput, 28% decreases in latency, and 5.7% improvements in fairness at best.

웹 기반 의료정보시스템 다중 접근제어를 위한 소프트웨어아키텍쳐 설계방법

노시춘,황정희 한국융합보안학회 2011 융합보안 논문지 Vol.11 No.4

웹 기반 의료정보는 많은 편리성을 제공하지만 공개된 네트워크 환경에서 나타나는 보안 취약성을 해결하지 않은 채 정보노출의 위험속에 사용이 확대되고 있다. 웹 기반 의료정보 접근시 보안문제에 대한 안전한 방법론 강구없이 기술만 발전시키려한다면 또 다른 위협의 요소를 증가시키는 것이다. 따라서 웹에 기반한 정보활용 보안대책 으로서 웹 기반 의료정보 접근제어 보안 메커니즘 기반 설계가 필요하다. 본 논문은 소프트웨어 아키텍쳐 설계사상을 기반으로 하여 의료정보시스템 접근제어 보안 메커니즘 기반을 설계 하였다. 그 방법론은 새로운 설계절차를 도출하고 아키텍쳐를 설계하며 기능 메커니즘 알고리즘을 구성하는 것 이다. 이를위해서는 웹 기반 다중 환자 정보 접근제어를 위한 보안 아케텍쳐 인프라스트럭가 필요하다. 제안하는 소프트웨어아케텍쳐는 소프트웨어 프레임워크를 도출하고 기능 메커니즘을 구성하는 기반에 관한 구조도를 도출했다. 제안된 시스템를 활용하여 의료정보 어플리케이션을 설계할때 의료정보 사용자는 실시간으로 데이터를 검색하면서도 통합화된 접근제어 알고리즘의 보장하에서 정보관리 안전성을 확보하는 시스템 설계가 가능하다. Web-based health information provides a lot of conveniences, however the security vulnerabilities that appear in the network environment without the risk of exposure in the use of information are growing. Web-based medical info rmation security issues when accessing only the technology advances, without attempting to seek a safe methodology are to increase the threat element. So it is required. to take advantage of web-based information security measures as a web-based access control security mechanism-based design. This paper is based on software architecture, design, ideas and health information systems were designed based on access control security mechanism. The methodo logies are to derive a new design procedure, to design architecture and algorithms that make the mechanism function. To accomplish this goal, web-based access control for multiple patient information architecture infrastructures is needed. For this software framework to derive features that make the mechanism was derived based on the structure. The proposed system utilizes medical information, medical information when designing an application user retrieves data in real time, while ensuring integration of encrypted information under the access control algorithms, ensuring the safety management system design.