• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.780-785
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• 2003

Recently the trends in information storage devices need small size, mobility, high capacity, and low power consumption etc. To satisfy those, the development of high performance actuator is an important issue. Compared with general linear actuator for optical disk drive, swingarm type rotary actuator is suitable to design in small form factor and has fast access time for random access. Swingarm actuator is designed considering the structural problem and the actuating force of VCM(Voice Coil Motor). The increase of mass caused by optical components makes vibration problems of swing-arm, therefore resonance frequency should be increased and inertia has to be reduced. ANSYS FEM tool is employed in optimizing swingarm. The VCM is designed using 3-D electro-magnetic analysis, and parameters of magnetic circuit are determined to matte large flux density. The large flux density enables to achieve low power consumption. VCM holder is designed to get the mass balance of total actuator and this balance reduces the magnitude of critical mode relative to pivot bearing, It is expected that swingarm type rotary actuator designed by this method is available to variable type of micro optical disk drives.

• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.67-75
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• 2009

The growing need for the mobility supportable networks induces the IP-based mobility management protocols. Though HMIPv6 which manages the micro-mobility of mobile nodes using MAPs suggests an effective method for mobility-support for mobile nodes within the domain that is managed by MAP. There is a problem that traffic may be concentrated on MAPs. In this paper, therefore, we proposed a method that can effectively distribute the traffic which is concentrated on a MAP under phased Mobile IPv6. In our proposed method, two or more MAPs are required and classified as an 'Active MAP' or a 'Passive MAP'. In addition, we defined the state of transition events between Active MAP and Passive MAP and the operations among MAPs for load distribution when an overload condition is occurred at some MAPs by traffic congestion. We compared the performance of our proposed method with its phased Mobile IPv6 to prove the propriety of our proposed method. As a result, we showed that our proposed method can provide an enhanced performance by about 12 percentages in view of packet throughput at the node.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.964-974
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• 2003

With increasing use of a personal mobile computer. the Mobile IPv6 is one of the main protocols that support mobility and complies with IPv6 specification. Similar to the mobile IPv6, the mobile IPv6 also has limitations on fast moving condition. The Hierarchical Mobile IPv6 is a solution that overcomes these limitations. The Hierarchical Mobile IPv6 is a micro mobility protocol that supports fast mobile IP handover and reduces signaling overhead with Mobility Anchor Point(MAP). But until now no paging method is applied to the Hierarchical Mobile IPv6 to reduce unnecessary signaling overhead and power consumption of mobile nodes. So, the paging mechanism for the Hierarchical Mobile IPv6 is proposed in this paper. the mechanism is implemented by making use of the destination option header and extension function and the last location algorithm. The results show that the Hierarchical Mobile IPv6 with the paging ability reduces the traffic of mobile networks by removing unnecessary binding update packet generated whenever handover takes place. Also, the larger the paging size is. the less the number of BU(Binding Update) massage generated.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.99-107
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• 2012

We propose control mechanism of UAV(Unmanned Aerial Vehicle) group for making the communication network to the base station after the target is found. We assume UAVs can communicate to each other by wireless LAN without existing communication infrastructure. UAVs started to fly in linear formation, after finding target, UAVs move to the base station to send the information about the target. At least one UAV stays the position that the target is found. This paper explains the mechanism supporting reliable connectivity during UAV group's flying. We verify the proposed scheme and evaluate the performance through NS-2 simulation. The proposed scheme can be applied to the disaster area and war zone, which the existing communication infrastructure cannot be worked.

• Journal of Digital Contents Society
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• v.7 no.3
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• pp.161-168
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• 2006

Wibro(Wibro - Wireless Broadband Internet ) is a system that can accept effectively the IP-based Wireless data traffic with upward / downward asymmetric transfer characteristic by using a Wirelss broadband transfer technology in OFDMA/TDD (Orthogonal frequency Division Multiple Access/Time Division Duplex). Wibro service should support handover to maintain connection continuously in movement because the service is based on If system which is different from cellular system. Current Micro Mobility system and general Mobile If system has got a problem of delayed speed and lost packets during handover. IETF protocol has been proposed for minimizing this problem and its standardization is under process, mainly focused on Mip4, Mip6 and Mipshop WG. This article studies and analyzes an effective method of minimizing handover delay to improve the problem of WiBro system and its revitalization & outlook.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.119-126
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• 2007

Recently, the mobility of users and mobile communication technologies have developed rapidly. The users in this state also want to connect their devices and to receive services anywhere, anytime. Hierarchical Mobile IPv6 (HMIPv6) has been proposed by the Internet Engineering Task Force (IETF) to compensate for such problems as handover latency and signaling overhead when employing Mobile IPv6 (MIPv6). HMIPv6 supports micro-mobility within a domain and introduces a new entity, namely Mobility Anchor Point (MAP) as a local home agent. However, HMIPv6 has been found to cause longer handover latency when the inter-domain handover occurs. This is because a Mobile Node (MN) has to generate two addresses and register them to Home Agent (HA) a MAP, respectively. In order to solve such problems, we propose a scheme that an MN generates one address and registers it to HA for supporting fast handover during the inter-domain handover process. In the proposed scheme, the load of MAP and MAP domain is reduced because the number of MNs which are managed by MAP is decreased and the MAP does not perform proxy Neighbor Discovery Protocol (NDP) to intercept packets destined to MNs. We evaluate the performance of proposed scheme in comparison to HMIPv6 through the simulation and numerical analysis.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.81-84
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• 2005

Various design schemes for network using wireless sensor nodes have been widely studied on the several application areas ranging from the real world information collection to environmental monitor. Currently, the schemes are focused on the design of sensor network for low power consumption, power-aware routing protocol, micro miniature operating system and sensor network middleware. The indoor localization system that identifies the location of the distributed nodes in a wireless sensor network requires features dealing with mobility, plurality and other environmental constraints of a sensor node. In this paper, we present an efficient location system to cope with mobility of multiple mobile nodes by designing a location handler that processes location information selectively depending on the nodes' density in a specific region. In order to resolve plurality of multiple mobile nodes, a routing method for the location system is also proposed to avoid the occurrence of overlapped location data.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.936-942
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• 2012

This review was to elucidate the fate of Bentazon(3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide) and its metabolites in soil. Bentazon is rapidly degraded to form polar metabolites which are mostly adsorbed to soil components, such as humin or fulvic acid, as non extractable forms and mineralized into $CO_2$ by light or micro-organisms in both aerobic or nonaerobic condition. The degradation of Bentazon is dependent on the rate of organic matters in soil and the use of land for the tillage. The degradation rate is decreased as the amount of organic matters in soil increases and if the land is under use for tillage. Sorption and mobility of Bentazon depends on soil pH and the content of organic matters in soil. Usually, the sorption of the metabolites of Bentazon is decreased with increase in the mobility and pH. Almost all of Bentazon is degraded within rhizosphere or forms conjugate bonds with soil organic matters before it reaches to the ground water.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.84-99
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• 2021

As the micro-mobility market grows, the demand for route guidance, that includes uphill information as well, is increasing. Since the climbing angle depends on the electric motor uesed, it is necessary to establish an uphill road DB according to the threshold standard. Although road alignment information is a very important element in the basic information of the roads, there is no information currently on the longitudinal slope in the road digital map. The High Definition(HD) map which is being built as a preparation for the era of autonomous vehicles has the altitude value, unlike the existing standard node link system. However, the HD map is very insufficient because it has the altitude value only for some sections of the road network. This paper, hence, intends to propose a method to generate the road longitudinal slope using currently available data. We developed a method of computing the longitudinal slope by combining the digital elevation model and the standard link system. After creating an altitude at the road link point divided by 4m based on the Seoul road network, we calculated individual slope per unit distance of the road. After designating a representative slope for each road link, we have extracted the very steep road that cannot be climbed with personal mobility and the slippery roads that cannot be used during heavy snowfall. We additionally described errors in the altitude values due to surrounding terrain and the issues related to the slope calculation method. In the future, we expect that the road longitudinal slope information will be used as basic data that can be used for various convergence analyses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.981-985
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• 2006

Wibro is stand for Wireless Broadband Internet called as Portable Internet, Wireless Broadband Internet or Wireless High-Speed Internet. This provides hish-speed internet service anytime, anywhere, from anyone and device with seamless mobility and the band is located between Mobile phone and wireless LAN. Wibro service should support handover to maintain connection continuously in movement because the service is based on If system which is different from cellular system. Current Mitre Mobility system and general Mobile If system has got a problem of delayed speed and lost packets during handover. IETF protocol has been proposed for minimizing this problem and its standardization is under process, mainly focused on Mip4, Mip6 and Mipshop WG. This article studies and analyzes an effective method of minimizing handover delay to improve the problem of WiBro system and its revitalization & outlook.