• Smart Structures and Systems
• /
• 제14권1호
• /
• pp.1-16
• /
• 2014

In this work, we address the so-called sensor reachback problem for Wireless Sensor Networks, which consists in collecting the measurements acquired by a large number of sensor nodes into a sink node which has major computational and power capabilities. Focused on applications such as Structural Health Monitoring, we propose a cooperative communication protocol that exploits the spatio-temporal correlations of the sensor measurements in order to save energy when transmitting the information to the sink node in a non-stationary environment. In addition to cooperative communications, the protocol is based on two well-studied adaptive filtering techniques, Least Mean Squares and Recursive Least Squares, which trade off computational complexity and reduction in the number of transmissions to the sink node. Finally, experiments with real acceleration measurements, obtained from the Canton Tower in China, are included to show the effectiveness of the proposed method.

• 한국정보통신학회논문지
• /
• 제6권6호
• /
• pp.863-872
• /
• 2002

Real-time(RT) object-oriented(00) distributed computing is a form of RT distributed computing realized with a distributed computer system structured in the form of an object network. Several approached proposed in recent years for extending the conventional object structuring scheme to suit RT applications, are briefly reviewed. Then the approach named the TMO(Time-triggered Message-triggered Object) structuring scheme was formulated with the goal of instigating a quantum productivity jump in the design of distributed time triggered simulation. The TMO scheme is intended to facilitate the pursuit of a new paradigm in designing distributed time triggered simulation which is to realize real-time computing with a common and general design style that does not alienate the main-stream computing industry and yet to allow system engineers to confidently produce certifiable distributed time triggered simulation for safety-critical applications. The TMO structuring scheme is a syntactically simple but semantically powerful extension of the conventional object structuring approached and as such, its support tools can be based on various well-established 00 programming languages such as C++ and on ubiquitous commercial RT operating system kernels. The Scheme enables a great reduction of the designers efforts in guaranteeing timely service capabilities of application systems.

• 정보처리학회논문지D
• /
• 제10D권7호
• /
• pp.1197-1206
• /
• 2003

본 연구에서는 인터넷 망을 기반으로 하는 인쇄 표준인 인터넷 인쇄 프로토콜(WP)에 대하여 소개하고 UP 클라이언트/서버 시스템 구현을 위하여 각 클라이언트와 서버의 기능에 대해 자세히 논의하였다. 특히 효율적인 IPP 클라이언트/서버 시스템 활용을 위하여 사용자그룹, 프린터그룹 등의 관리기법을 채택하여 시스템 운영자와 관리자의 기능을 강화하고 효과적으로 IPP 시스템 사용자나 프린터를 관리할 수 있도록 구현하였다. 또한 IPP 표준옳 사용하는 타 회사 제품과의 호환성을 최대한 확보하는데 노력하였다. 그리고 마지막으로 앞으로의 연구 방향을 제시하였다.

• 한국시스템다이내믹스연구
• /
• 제3권1호
• /
• pp.5-42
• /
• 2002

The main purpose of this paper is analyzing long-term growth possibility of a telecommunication Company (Telco) H. First of all, to achieve this purpose, the precise understanding about causal relations among growth and decay factors of Telco H is required. Based upon the causal analysis, a basic computer simulation model is developed. Finally, several predictive examinations about growth possibility and pattern of the Telco H are conducted using three scenarios. From simulation results, the most important policy leverages are capabilities of market share sustenance, improvement of service quality and squeezing current network facility to elevate profitability and efficiency. Recently, telecommunication industry has become more and more competitive due to introduction of Internet and deregulation. Internet has brought about global competition as well as confusion between telecommunication and broadcasting industries. At the almost same time, deregulation is a universal tendency and a catalyst of unlimited competition. Telco H has been a dominant company in Korea for last century. However, the dominant position of Telco H has been threatened by the change of competition environment. The competitive environment has many elements and keeps changing dynamically. Therefore, System Dynamics simulation methodology is adopted to examine the problem.

• 한국재난정보학회 논문집
• /
• 제1권1호
• /
• pp.43-71
• /
• 2005

Terrorism is the use of violence, especially murder and bombing, in order to achieve political aim or to force a government to do something. Nowadays, instrument of mass destruction are smaller, cheaper, and more readily available. Cellular phones were used as timers in the attacks in Madrid last March. Hijacking an airplane is relatively inexpensive. Finally, the information revolution provides inexpensive means of communication and organization that allow groups once restricted to local and national police jurisdictions to become global. Al Qaeda is said to have established a network in fifty or more countries. These technological and ideological trends increased both the lethality and the difficulty of managing terrorism. Because of the unprecedented scale of Al Qaeda's attacks, the focus is properly on Islamic extremists. But it would be a mistake to limit our concern solely to Islamic terrorists, for that would ignore the way that technology is putting into the hands of deviant groups and individuals' destructive capabilities that were once limited primarily to governments and armies.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권10호
• /
• pp.4080-4097
• /
• 2020

In recent years, convolutional neural network (CNN) has become the primary method for face detection. But its shortcomings are obvious, such as expensive calculation, heavy model, etc. This makes CNN difficult to use on the mobile devices which have limited computing and storage capabilities. Therefore, the design of lightweight CNN for face detection is becoming more and more important with the popularity of smartphones and mobile Internet. Based on the CPU real-time face detector FaceBoxes, we propose a multi-task lightweight face detector, which has low computing cost and higher detection precision. First, to improve the detection capability, the squeeze and excitation modules are used to extract attention between channels. Then, the textual and semantic information are extracted by shallow networks and deep networks respectively to get rich features. Finally, the landmark detection module is used to improve the detection performance for small faces and provide landmark data for face alignment. Experiments on AFW, FDDB, PASCAL, and WIDER FACE datasets show that our algorithm has achieved significant improvement in the mean average precision. Especially, on the WIDER FACE hard validation set, our algorithm outperforms the mean average precision of FaceBoxes by 7.2%. For VGA-resolution images, the running speed of our algorithm can reach 23FPS on a CPU device.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권6호
• /
• pp.1689-1706
• /
• 2012

The preservation of temporal dependencies among a group of processes that exchange continuous media at runtime is a key issue for emerging mobile distributed systems (MDS), such as monitoring of biosignals and interactive multiuser games. Although several works are oriented to satisfy temporal dependencies, most of them are not suitable for MDSs. In general, an MDS is characterized by the absence of global references (e.g. shared memory and wall clock), host mobility, limited processing and storage capabilities in mobile hosts, and limited bandwidth on wireless communication channels. This paper proposes an asymmetric synchronization protocol to be used at runtime in an MDS without using a common reference. One main aspect of our synchronization protocol is that it translates temporal constraints to causal dependencies of the continuous media data as seen by the mobile hosts. We simulate the protocol by considering a cellular network environment and by using MPEG-4 encoders. The simulation results show that our protocol is effective in reducing the synchronization error. In addition, the protocol is efficient in terms of processing and storage costs at the mobile devices, as well as in the overhead attached per message across the wired and wireless channels.

• 한국CDE학회논문집
• /
• 제13권2호
• /
• pp.131-138
• /
• 2008

With the advancements of the Internet and CAD data translation techniques, more CAD models are transferred from a CAD system to another through the network and interoperability is getting a common word in the CAD industry. However, when a CAD model is translated for an incompatible system into a neutral format such as STEP or IGES, its precious feature information is lost. When this feature information is lost, the advantage of feature based modeling is not valid any longer, and modification for the model is purely dependent on geometric and topological manipulations. However, the capabilities of the existing methods to modify these feature-independent models are limited as the modification involves a topological change in the model. To address this issue, we present a volumetric method to modify the solid models in neutral format. First, this method selectively decomposes the solid model to separate the portion of interest called feature volume. Next, the designer modifies the feature volume without concerning a topological change. Finally, the feature volume is united with the original solid model to complete the modification process. The results of test cases are presented to attest the usefulness of the proposed method.

• Journal of Communications and Networks
• /
• 제15권4호
• /
• pp.422-429
• /
• 2013

Advances in wireless sensor network (WSN) technology have enabled small and low-cost sensors with the capability of sensing various types of physical and environmental conditions, data processing, and wireless communication. In the WSN, the sensor nodes have a limited transmission range and their processing and storage capabilities as well as their energy resources are limited. A triple umpiring system has already been proved for its better performance in WSNs. The clustering technique is effective in prolonging the lifetime of the WSN. In this study, we have modified the ad-hoc on demand distance vector routing by incorporating signal-to-noise ratio (SNR) based dynamic clustering. The proposed scheme, which is an efficient and secure routing protocol for wireless sensor networks through SNR-based dynamic clustering (ESRPSDC) mechanisms, can partition the nodes into clusters and select the cluster head (CH) among the nodes based on the energy, and non CH nodes join with a specific CH based on the SNR values. Error recovery has been implemented during the inter-cluster routing in order to avoid end-to-end error recovery. Security has been achieved by isolating the malicious nodes using sink-based routing pattern analysis. Extensive investigation studies using a global mobile simulator have shown that this hybrid ESRP significantly improves the energy efficiency and packet reception rate as compared with the SNR unaware routing algorithms such as the low energy aware adaptive clustering hierarchy and power efficient gathering in sensor information systems.

• 한국중재학회지:중재연구
• /
• 제16권3호
• /
• pp.191-216
• /
• 2006

It has been talked about the responsibility of the South-North Korean e-market place(e-MP) collaboration project every you since 2003. However, the feasibility as the business has not been dealt with in detail due to the uncertain environment as well as the complicated procedures of the project. The research focuses on the workable mechanism of the South-North Korean E-Market Place collaboration project. The feasibility of the project results from the newly installed fiber telecommunication network as well as the 1 billion dollars of the trading volume between South and North Korea. The research analyzes on the capabilities as well as willingness of the South and North Korea for the e-MP, and concludes with two paradigms of the future tasks. First, the unified but step-wise structure should be made to promote the project by the political committee (South and North Korea EC Committee) and the economical administration body (South and North Korea EC Corporation). Second, the market-oriented resolution system such as South and North Korea Arbitration Body should be involved to create legal environment. Above all, the discussion should be on the main body of e-MP settlement to abolish the psychological as well as practical barriers to enter the South-North Korean electronic commerce.