• The KIPS Transactions:PartD
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• v.14D no.6
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• pp.649-656
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• 2007

Today, controller area network(CAN) is a field bus that is nowadays widespread in distributed embedded systems due to its electrical robustness, low price, and deterministic access delay. However, its use safety-critical applications has been controversial due to dependability limitation, such as those arising from its bus topology. Thus it is important to analyze the performance of the network in terms of load of data bus, maximum time delay, communication contention, and others during the design phase of the controller area network. In this paper, a simulation algorithm is introduced to evaluate the communication performance of the vehicle network and apply software base fault injection techniques. This can not only reduce any erratic implementation of the vehicle network but it also improves the reliability of the system.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.53-65
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• 2005

This paper presented a mechanism of the soil structure reinforced by geosynthetics, in which the reinforcing mechanism is treated as the effect arising from the reinforcement process to prevent the dilative deformation of soil under shearing. A full-scale in-situ model test was carried out by introducing the prestress method to enhance the geosynthetic-reinforcement, and the prestress effect through the FEM is also examined. The elasto-plastic model and the initial parameters needed in the FEM are presented. Moreover, the theoretical prediction is compared with the experimental results, which were obtained by a full-scale in-situ model test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.673-675
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• 2010

This paper proposes the adaptive class-E power amplifier with maintaining high power added efficiency (PAE) in 400MHz range. This amplifier is used a microprocessor to adapt a resonator circuits and to maintain high efficiency in case of input frequency variation. To validate the adaptive amplifier operation, which is a 450MHz operating frequency and a 100MHz bandwidth, the class E amplifier is implemented. As a result, the adaptive amplifier is maintained above 60% efficiency and has a 74.8% maximum efficiency.

• The KIPS Transactions:PartC
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• v.15C no.1
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• pp.51-60
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• 2008

Micro-mobility protocols have been developed to reduce the control message overhead due to movements of mobile nodes. With the spread of mobile devices, services using mobile nodes are increasing and multicast services are becoming more important in providing multimedia services. In this paper we propose a new multicast protocol suitable for micro-mobility environments. The proposed protocol is designed to maintain optimal multicast routing paths and continue to provide multicast services without disruption in spite of frequent handoffs due to movements of mobile nodes. We used simulation to evaluate the proposed protocol, compared its performance with existing multicast protocols for mobile environments including bi-directional tunneling, remote subscription, and MMA, and observed that the proposed protocol exhibited better performance in terms of transmission success ratio and overhead on the network.

• Journal of the Korean Orthopaedic Association
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• v.55 no.6
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• pp.457-471
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• 2020

Fingers are body parts with a complex structure and essential functions that are the most prone to trauma. The principle of treatment for finger fractures is to determine the balance between obtaining stable fracture fixation and early joint movement. Despite proper treatment, there are many cases of functional and cosmetic problems caused by stiffness or deformation as complications. This review article introduces the latest knowledge in the treatment of finger fractures focusing on fractures and dislocations around the interphalangeal joints, including joint surface damage, which is difficult to treat and leads to poor results. This article consists of fracture cases and describes the methods and solutions to address these complications.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.1
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• pp.8-12
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• 1985

In the pure Phragmites communis grassland in the lower course of Nakdong river, the seasonal changes of standing crop and productive structure, annual changes of the maximum standing crop, and annual net production were estimated. The maximum standing crop of the pure P. communis grassland is on mid-September, the maximum average daily productivity was $32.7g/m^2/day$ from June to July. The leaf area index of the pure reed grassland increased to July, and then decreased slowly. The logitudinal growth of above-ground parts of the reed grassland was maximum state, 320cm, on mid September. Annual net production was $3,399g/m^2/year$, and it suggests that grassland is stable. Productive structure of the pure reed grassland indicated that the distribution of leaf was concentrated on the upper parts according to the grassland maturation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.375-390
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• 2004

Domain Name System(DNS), one of the most important Internet services, handles mapping from host names to Internet addresses and vice versa, and precedes many Internet applications such as Web, e-mail, file transfer, etc. In this paper, we propose a structural design of a generic name server system providing name services for a huge domain for the purpose of improving the performance as well as the reliability of the system. We demonstrate the validity of the design by implementing and running a testbed system. Our testbed employs a couple of master name sowers for distributing the service overhead over two, rather than one, servers and for achieving high availability of the system as a whole. We suggest the use of dynamic update to add and delete records from a zone for which the name server has authority. The slave name servers located remotely then get a new, updated copy of the zone via incremental zone transfers(IXFRs). The experiments with the implemented testbed show that the proposed structure would easily manage increasing demands on the server power, and be highly available in the face of transient faults of a module in the system.

• Journal of Wetlands Research
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• v.7 no.4
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• pp.43-50
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• 2005

Wetlands can transform or remove pollutants from water body, such as nitrogen, phosphate, and organics. Many researches were conducted in relation to uptake process by aquatic plants in wetlands. However, water purification processes in wetlands are the results of physical, chemical and biological, especially microbiological reactions. As such, understanding on microbial processes is of great importance. In this study, we used pondor marsh-type wetland microcosms for investigating the water purification capacity and microbial functions, namely, extracellular enzyme activities, nitrification and denitrification. In a pond system, removal efficiencies of $NO_3{^-}$ and $PO{_4}^{3-}$ were 96% and 100 % respectively, while those in a marsh system were 94%, 100% respectively. These high removal efficiencies appeared to be caused by high adsorption ability to soils and microbial functions in wetland.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.42-52
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• 1997

The basic principle of underwater ram-jet as a unique marine propulsion concept showing vary high cruise speed range(e. g. 80-100 knots) is the thrust production by the transfer of the potential energy of compressed gas to the operating liquid through kinetic mixing process. This paper is aimed to investigate the propulsive efficiency of the nozzle flow in underwater ram-jet at the speed of 80 knots for the buried type vessel. The basic assumption of the theoretical analysis is that mixture of water and air can be treated as incompressible gas. For an optimized nozzle configuration obtained from the performance analysis, preliminary data for performance evaluation are obtained and effects of nozzle inner wall friction, ambient temperature, ambient pressure, water density, gas velocity, bubble radius, flow velocity, diffuser area ratio, mass flow ratio and water velocity gradient are investigated.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.3
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• pp.19-22
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• 2013

Recently, high speed transmission and large information demand have been increased. Also, researches of integrated optical device for large production and high-efficient planar lightwave circuit (PLC) have been increased. In this paper, integrated optical alignment is proposed which makes passive alignment between optical device and optical fiber possible. The integrated optical device consists of splitter structures which have one input and two outputs. The proposed integrated structure was fabricated by roll-to-roll (RTR) processing method. This method enables to manufacture continuously and the processing time can be shortened. Optical property of the fabricated optical device showed 3.9 dB insertion loss and 0.2 dB optical uniformity using the light source with 1550 nm wavelength.