• 한국컴퓨터정보학회논문지
• /
• 제22권9호
• /
• pp.33-40
• /
• 2017

In this paper, we propose a sink-location management and data-routing scheme to effectively support the mobile sink in solar-powered WSN. Battery-based wireless sensor networks (WSNs) have a limited lifetime due to their limited energy, but solar energy-based WSNs can be supplied with energy periodically and can operate forever. On the other hand, introduction of mobile sink in WSNs can solve some energy unbalance problem between sink-neighboring nodes and outer nodes which is one of the major challenges in WSNs. However, there is a problem that additional energy should be consumed to notify each sensor node of the location of the randomly moving mobile sink. In the proposed scheme, one of the nodes that harvests enough energy in each cluster are selected as the cluster head, and the location information of the mobile sink is shared only among the cluster heads, thereby reducing the location management overhead. In addition, the overhead for setting the routing path can be removed by transferring data in the opposite direction to the path where the sink-position information is transferred among the heads. Lastly, the access node is introduced to transmit data to the sink more reliably when the sink moves frequently.

• 한국지능정보시스템학회:학술대회논문집
• /
• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
• /
• pp.179-185
• /
• 2001

Mobile agents have the unique ability to transport themselves from one system in a network to another. The ability to travel allows mobile agents to move to a system that contains services with which they want to interact and then to take advantage of being in the same host or network as the service. But most of conventional mobile agent systems require that the users or the programmer should give the mobile agent its detail behavioral script for accomplishing the given task. And during its runtime, such mobile agents just behave according to the fixed script given by its user. Therefore it is impossible that conventional mobile agents autonomously build their own plants and execute them in considering their ultimate goals and the dynamic world states. One way to overcome such limitations of conventional mobile agent systems is to develop an intelligent mobile agent system embedding a reactive planner. In this paper, we design both a model of agent mobility and a model of inter-agent communication based upon the representative reactive planning agent architecture called JAM. An then we develop an intelligent mobile agent system with reactive planning capability, IMAS, by implementing additional basic actions for agent moves and inter-agent communication within JAM according to the predefined models. Unlike conventional mobile agents. IMAS agents can be able to adapt their behaviors to the dynamic changes of their environments as well as build their own plans autonomously. Thus IMAS agents can show higher flexibility and robustness than the conventional ones.

• 대한산업공학회지
• /
• 제25권3호
• /
• pp.342-350
• /
• 1999

Two location algorithm (TLA) considers two location areas (LAs) to track the location of a mobile station (MS). The TLA significantly outperforms the single location algorithm when the call-to-mobility ratio (CMR) is low (i.e., the user moves more frequently than to receive calls). However, because of the paging cost for the users moving back to the previously visited LA, the performance of the TLA degrades when the CMR is high. To reduce those paging cost, we propose the new algorithm called TLA with call information (TLAC). In TLAC, we use the location information of the MS within the setup message when the MS originates a call in the previously visited LA. Through the setup message, the system can know the exact location of the MS without the additional location registration operation, and the paging cost for the arriving calls in the visited LA can be reduced. An analytical model is proposed to compare the TLAC and previous TLA protocol. Our study indicates that the TLAC always guarantees better performance than the TLA. We also observe that the TLAC is much better than the TLA when the CMR is high.

• 대한조선학회 특별논문집
• /
• 대한조선학회 2009년도 특별논문집
• /
• pp.123-129
• /
• 2009

Ship painting procedures can be divided into two categories; Out-shell plate painting of the hull and the interior painting of each double gull blocks. It is really hard to apply standardized and automated operations to the latter because the double hull blocks contains a variety of complicated supportive materials and pipes to strengthen the ship structure. In addition their poor working conditions cause painting workers to avoid working in them, resulting in the waste of paints and additional pollution issues. So this research, successfully focused on overcoming the difficulties in working in the complicated blocks and the tough working conditions introduces the main details of automatic equipment systems and their transfer algorism which show how the equipment paints the inner sides of a longitudinal stiffener and moves to another automatically.

• 한국군사과학기술학회지
• /
• 제16권3호
• /
• pp.332-339
• /
• 2013

The network nodes in a tactical network moves continuously and due to the physical and electronic obstacles, the connections are not always available. Due to the frequent disconnections, it is hard to discover the path among the nodes in a DTN. According to PROPHET(Probabilistic Routing Protocol using History of Encounters and Transitivity), one of the most well-known DTN routing protocols, a DTN node determines whom to forward a packet according to the packet delivery probability. From the viewpoint of a node, the packet delivery probability of another node is degraded while the nodes are disconnected whereas it is improved when they encounter. In this paper, we enhance the algorithm estimating the packet probability by considering the encounter count as an additional parameter. Our algorithm prefers the node that encounters the destination more frequently in selecting the next hop toward the destination. We evaluated the performance of our algorithm by simulating military operations using a DTN-dedicated simulator. Through the simulations, we show that our proposed algorithm achieve higher packet delivery ratio with similar overhead compared with PROPHET.

• 대한전자공학회논문지SD
• /
• 제47권4호
• /
• pp.1-6
• /
• 2010

정지해 있는 물체가 디스플레이 될 때는 상이 선명하지만 움직이는 물체가 디스플레이 될 때는 물체의 가장자리가 번져 보이는 Motion Blur현상이 일어난다. 이러한 문제점을 개선하기 위하여 본 논문에서는 XUP Virtex-II Pro Development System을 이용하여 Virtex-II Pro XUP XC2VP30 보드에 Motion Blur를 줄이는 Overdrive 기술을 구성하는 것을 목표로 하였다. 구현된 플랫폼은 하드웨어 IP로 구현하였으며 어플리케이션 및 모델 데이터 인터페이스는 소프트웨어에서 처리하도록 하였다. 본 설계에서는 임의의 동영상 모델을 이용하여 동영상의 이동 속도(Pixel/Frame)에 따른 Blur의 정도와 기존의 Overdrive를 제어하였을 경우 발생하는 역잔상을 개선하였고, 동영상에서 보다 선명한 화질이 구현될 수 있음 보여주었다.

• ETRI Journal
• /
• 제34권2호
• /
• pp.216-225
• /
• 2012

This paper presents a transceiver module for human body communications whereby a spread signal with a group of 64 Walsh codes is directly transferred through a human body at a chip rate of 32 Mcps. Frequency selective digital transmission moves the signal spectrum over 5 MHz without continuous frequency modulation and increases the immunity to induced interference by the processing gain. A simple receiver structure with no additional analog circuitry for the transmitter has been developed and has a sensitivity of 250 ${\mu}V_{pp}$. The high sensitivity of the receiver makes it possible to communicate between mobile devices using a human body as the transmission medium. It enables half-duplex communication of 2 Mbps within an operating range of up to 170 cm between the ultra-mobile PCs held between fingertips of each hand with a packet error rate of lower than $10^{-6}$. The transceiver module consumes 59 mA with a 3.3 V power supply.

• 한국결정성장학회지
• /
• 제26권3호
• /
• pp.121-125
• /
• 2016

The effect of temperature and pressure in the nitrogen ambient furnace on bulk micro defect (BMD) and denuded zone (Dz) is experimentally investigated. It is found that as pressure increases, Dz depth increases with a small decrease of BMD density in the range of temperature, $100{\sim}300^{\circ}C$. BMD density with hot isostatic pressure treatment (HIP) at temperature of $850^{\circ}C$ is higher than that without HIP while Dz depth is lower due to much higher BMD density. As the pressure increases, BMD density is increased and saturated to a critical value, and Dz depth increases even if BMD density is saturated. The concentration of nitrogen increases near the surface with increasing pressure, and the peak of the concentration moves closer to the surface. The nitrogen is gathered near the surface, and does not become in-diffusion to the bulk of the wafer. The silicon nitride layer near the surface prevents to inject the additional nitrogen into the bulk of the wafer across the layer. The nitrogen does not affect the formation of BMD. On the other hand, the oxygen is moved into the bulk of the wafer by increasing pressure. Dz depth from the surface is extended into the bulk because the nuclei of BMD move into the bulk of the wafer.

• 한국통신학회논문지
• /
• 제39C권9호
• /
• pp.782-788
• /
• 2014

본 논문은 무선 네트워크에서 하나의 단말기가 복수의 인터페이스를 이용하여 상이한 액세스 네트워크에 접속할 때 QoS에 따른 플로우 이동성 지원을 위한 방안을 제안한다. 이를 위해서 PBU/PBA 메시지의 확장 및 LMA에 추가적인 QoS request 메시지 절차 추가하였다. 제안한 방법을 통해 LMA가 이동할 네트워크에 대한 QoS정보를 수집하고 플로우 이동을 결정하여 사용자에게 네트워크 상황에 따른 최적의 서비스를 제공할 수 있다. 제안한 방안은 state transition diagram을 이용하여 수행 여부를 확인하였다.

• 한국재료학회지
• /
• 제14권5호
• /
• pp.315-321
• /
• 2004

The void evolution in direct bonding process of $Si/Si_3$$N_4$ ∥ $SiO_2$/Si silicon wafer pairs has been investigated with an infrared camera. The voids that formed in the premating process grew in the conventional furnace annealing process at a temperature of $600^{\circ}C$. The voids are never shrunken even with the additional annealing process at the higher temperatures. We observed that the voids became smaller and disappeared with sequential scanning by our newly proposed fast linear annealing(FLA). FLA irradiates the focused line-shape halogen light on the surface while wafer moves from one edge to the other. We also propose the void shrinking mechanism in FLA with the finite differential method (FDM). Our results imply that we may eliminate the voids and enhance the yield for the direct bonding of wafer pairs by employing FLA.