• Journal of KIISE:Software and Applications
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• 제36권3호
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• pp.200-207
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• 2009

U-Healthcare is more efficient as a solving method for health problems rather than visiting the hospital. Recently, systems have been studied to offer appropriate service to user, which gather and analyze biological signals of a user and context information around the user from a variety of sensors. The existing systems for U-Healthcare are based on domain specific service so it is difficult to expand and link to other systems. Also, they lack services focusing on the specific quality of the user, because they offer a general service which targets a lot of users. To address this problem, we expand an extensibility of system using the context-awareness agent based on multi-agents. Also, we provide the suitable services which match with the context information of user to each user using the modeling toolkit JaUCE based on GUI. We design and implement U-Silvercare service to demonstrate the effectiveness of the proposed context-awareness agent and modeling toolkit.

• Journal of Information Processing Systems
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• 제6권3호
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• pp.269-294
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• 2010

The interconnection of mobile devices in urban environments can open up a lot of vistas for collaboration and content-based services. This will require setting up of a network in an urban environment which not only provides the necessary services to the user but also ensures that the network is secure and energy efficient. In this paper, we propose a secure, energy efficient dynamic routing protocol for heterogeneous wireless sensor networks in urban environments. A decision is made by every node based on various parameters like longevity, distance, battery power which measure the node and link quality to decide the next hop in the route. This ensures that the total load is distributed evenly while conserving the energy of battery-constrained nodes. The protocol also maintains a trusted population for each node through Dynamic Trust Factor (DTF) which ensures secure communication in the environment by gradually isolating the malicious nodes. The results obtained show that the proposed protocol when compared with another energy efficient protocol (MMBCR) and a widely accepted protocol (DSR) gives far better results in terms of energy efficiency. Similarly, it also outdoes a secure protocol (QDV) when it comes to detecting malicious nodes in the network.

• Journal of the Institute of Electronics Engineers of Korea CI
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• 제47권2호
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• pp.39-47
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• 2010

In Wireless Sensor Network, transmission errors are frequently occurred due to the node failure, battery discharge, and interference by objects. Although Directed Diffusion has been considered as a prominent Data-centric routing algorithm, it revealed some weaknesses at this kind of unexpected network errors. In order to address the problem, we proposed a radio-aware routing algorithm for improving reliability of Directed Diffusion in Wireless Sensor Networks. The proposed algorithm is aware of the network status based on the radio information of MAC and PHY layers using a cross-layer approach. The link quality and the node failure information from the acquired network status were used to decide an alternative path to provide a reliable data transmission in error-prone sensor networks. The proposed algorithm showed its effectiveness of the data delivery rate and data ratio with several simulations consisting of various error rates and the number of nodes.

• Journal of Environmental Policy
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• 제3권2호
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• pp.59-87
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• 2004

In its Declaration of Principles, the United Nations Conference on Environment and Development recommends that, "to achieve sustainable development and a higher quality of life for all people, states should reduce and eliminate unsustainable patterns of production and consumption...." This notion of sustainability lies at the core of many "commons" problems, where the central issue is to enable "individuals to sustain long-term, productive use of natural resource systems". In other worlds, a common definition of "sustainability" captures the idea of aligning human consumption with the capacity of ecological systems to supply, over a long period of time, such natural resources as air, soil, or water on which production depends. The concept of sustainability raises all sorts of political, social, and economic questions about the distribution of environmental protection. For sustainable community development to be addressed, these questions must be raised. In order to convince different citizenry of the necessity of sustainability, these questions must also be answered. This is where questions of equity, justice, and fairness arise. Sustainability and equity require that we deal with nature as an undivided whole, with no part being unsustainable. Sustainability and social policy also requires that we deal with the human population as an undivided whole. We simply cannot move people around the planet to either perpetuate past practices of earth exploitation or to implement sustainable planning. Everyone must work with the people inhabiting sensitive ecological areas, especially areas of regeneration. In the sustainable global community, we are as strong as our weakest link, or our most toxic community. This is the undeniable driving force for the infusion of equity into the sustainable development debate.

• Journal of the Korea Institute of Building Construction
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• 제12권3호
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• pp.340-346
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• 2012

Recently, the construction industry has been pursuing the rationalization of its various systems through informatization. Procurement is a highly important element of the construction process, as it is directly related to the cost and quality of a construction project. In addition, procurement management of resources is in an indivisible relation, so that it is significant to link each other effectively. This study proposed construction activity and basic data connected to cost summary work for the categorization and utilization of resources. This study connected that activity to detailed items of material and labor cost, and proposed a procurement planning model of resources by activity that can utilize all resources and information. In addition, this model can classify resources and information by various forms. We found that the utilization of this procurement planning model will be higher because it can grasp various problems that occur in the passive procurement and provide additional functions that can be modified.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제24권12B호
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• pp.2298-2319
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• 1999

In this paper, we propose a new moving mobile base station (MMBS) scheme for very low power and micro-size RMIMS (radio-interfaced micro information monitoring system) terminals. RMIMS terminals can be used in various application service areas such as pollution monitoring, environment surveillance, traffic monitoring, emergency monitoring (e.g., building, bridge, railroad breakdown), security monitoring (e.g., theft, alarm) and military application. For these applications based on wireless transmission technologies, sensor type RMIMS terminals must satisfy low cost and low power design (e.g., solar power, life limited battery) requirement. In RMIMS terminal design, this low power requirement limits transmission range of uplink or reverse link and means small cell size. Also these applications using RMIMS terminals may have a little bit non real-time traffic characteristic and low scattering density in service area.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권9호
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• pp.1654-1662
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• 2006

An ad hoc network is multi-hop network composed of radio links. and the transmission quality of a radio link is more unstable than that of a wired circuit. Packet loss thus occurs frequently in an ad hoc network, and the consequent connection failure results in a severe deterioration of TCP performance. TCP performance also deteriorates because of the collision of data packets and ACK packets in the radio channel. In this paper we study to improve the performance of the Mobile Ad-hoc network by using Delayed ACK algorithm with our proposed ODA(Ordering-Delayed ACK) method. The proposed ODA algorithm increases the number of the data packets orderly at the receiver side which is going to be applied for the Mobile Ad-hoc network. We accomplished a computer simulation using NS-2. From the simulation results, we find the proposed ODA algorithm obviously enlarge the channel capacity and improve the network performance at the situation of multi-hop of ad-hoc network than the existing Delayed ACK algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제14권1호
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• pp.115-121
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• 2010

As internet becomes widespread, a lot of information is opened to public and users of Internet can access effectively information using web searching service. To construct web searching service, the web searching method for collecting of information is needed to obtain web page view. As a number of web page view increases, it is necessary to collect information of high quality information to be searched, therefore, a variety of web engine for searching mechanism is developed. Method of link extraction with javascript in dynamic web page and design of web searching robot are presented m this paper. To evaluate performance analyzes, we fixed one searching model with the proposed method. The searching time takes 2 minute 67 sec for 299 web pages and 12.33 sec for 10 searching model.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권11호
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• pp.2553-2562
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• 2013

It is difficult for TCP congestion control algorithm to ensure the bandwidth and delay bound required for media streaming services in broadband wireless network environments. In this paper, we propose the COIN TCP (COncave INcrease TCP) scheme for providing a high-quality media streaming services. The COIN TCP concavely increases the congestion window size by adjusting the increment rate of congestion window, that is inversely proportional to the amount of data accumulated in the router queue. As a result, our scheme can quickly occupy the available bandwidth and prevent the heavy congestion. It also improves the link utilization by adjusting the decrement rate of congestion window according to the packet loss rate with the random loss. Through the simulation results, we prove that our scheme improves the total throughput in broadband wireless network.

• The Transactions of the Korea Information Processing Society
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• 제7권8S호
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• pp.2608-2619
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• 2000

This paper proposes the Handover Scheme for the mobile and describes the result of the performance analysis. In the conventional scheme of handover request, the withdrawal of terminal may occur because handover request is performed based on fixed signal level without considering network load and terminal mobility. The proposed scheme offers the minimization of withdrawal and handover blocking probability by means of the handover request of terminal based on the network load and terminal mobility. Conventional handover scheme has the sequential procedure that network performs resource check and path rerouting on the handover by MT(Mobile Terminal). Proposed handover scheme pre-processes the resource check before the handover request by predicting the handover request timo so that handover latency can be reduced. Moreover, path optimization is executed after the completion of handover in order to reduce handover latency. The rdduction of handover latency prevents the dropping of service by minimizing backward handover blocking. In summary, we propose the prediction of handover request time and decision method based on terminal, validating the performance of proposed scheme considering various cases of simulation.