• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.2
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• pp.41-49
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• 2002

This paper describes on the initial procedure of the concept development for marine waste cleaning ships and her fleets. We investigated and analyzed about missions, operating ocean environments; similar cleaning ships, laws and regulations for determining the functional requirements of ships and fleets, and then top-level requirements were drawn out. According to the volume estimation of marine wastes in domestic coastal and shoreline, we made the alternatives, combination of some design factors, for the evaluation of economical efficiency. As a result of this study, we organized the fleets of marine waste cleaning ships adapted to the environments of domestic coastal.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.980-986
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• 2012

In this paper we develop a minimalist model of single molecule spectroscopy in a dynamic environment. Our model is based upon a lattice system consisting of a probe molecule embedded in an Ising-model like environment. We assume that the probe molecule interacts with the Ising spins via a dipole-dipole potential, and calculate free energy curves and lineshapes of the system. To investigate fluctuation behavior of the system we exploit the metadynamics sampling method. In particular, using the method, we calculate the free energy curve of magnetization of the lattice and that of the transition energy of the probe molecule. Furthermore, we compare efficiencies of three different sampling methods used; unbiased, umbrella, and metadynamics sampling methods. Finally, we explore the lineshape behavior of the probe molecule as the system undergoes a phase transition from a sub-critical and to a super-critical temperature. We show that the transition energy of a probe molecule is broadly distributed due to the heterogeneous, local environments.

• Progress in Superconductivity
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• v.8 no.2
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• pp.193-201
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• 2007

Since the margins for the minimum quench energy and for the operating current in the superconducting magnet determine the operating regime of the magnet, a thermal stability analysis for the KSTAR superconducting magnet system is performed using 1-D Gandalf code. The result shows that the minimum quench energy is about 500 mJ/cc and the operating current margin is about 70 %. These values are larger than those of the KSTAR design criteria and the KSTAR superconducting magnet system can be operated stably under various experimental environments.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.131-134
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• 2008

A Mobile Ad hoc NETwork(MANET) is a system of wireless mobile nodes that dynamically self-organize in arbitrary and temporary network topologies. In the highly dynamic environment of MANET, energy efficiency is an important performance measure since it directly affects the network lifetime. The failure of energy severely impacts a communications system in crucial communications environments, such as disasters salvage. In this study, we propose a new packet switching routing that can increase the durability of the energy resource and therefore, the lifetime of the mobile nodes and MANET. The performance of the packet switching routing on the node-disjoint multipath and that of AODV are compared by NS2 simulation. The simulation results indicate that this new switching routing can extend the lifetime of a MANET.

• The Journal of the Acoustical Society of Korea
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• v.12 no.1
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• pp.47-54
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• 1993

Performance analysis is very important to transmit the high quality information and to construct the optimal system for the minimze the noise from the channel of spread spectrum system. In this paper the error rate performance is analyzed with computer simulation in noncoherent frequency hopping M-qry frequency shift keying(FH/MFSk) systems with regard to thermal noise under the partial band jamming environments. AS a result, in case the thermal noise is disregarded, bit error probability of system in jamming fraction ρ and Eb/Nj(bit energy to jamming power density) is reduced with the increase of K and in worst case 32FSK system is better than 2FSK system by 3.23dB with the variatio of Eb/Nj. In case thermal noise is considered, bit error probability of system by 3.23dB with the variation of Eb/Nj. In case thermal noise is considered, bit error probability of system are reduced with the increase of K and Eb/No(bit energy to thermal noise density). Bit error probability in connection with worst case ρ is not largely influenced form over the 14dB to K=1 and 8dB to K=5 accordingly thermal noise disregarding. These results may be useful for avoiding the common vulnerabilities when the spread spectrum system is designed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.40-52
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• 2001

Using a biochemical indicator, the effects of fecal pollution in the estuary of the Nakdong river and in the Chinhae Hay were investigated from summer to winter in 1997-1998. The biochemical indicator used in this study was coprostanol (5-cholestan-3-ol) which is a kind of fecal sterol. It is a useful tracer of fecal pollution, as it is only found in feces of mammals including humans. Coprostanol was less affected by surrounding environments than other indicators of fecal pollution such as fecal coliform or ammonium and was proved to be a good indicator of fecal pollution. Therefore, long-term observations of coprostanol and related compounds could be used as useful indicators for the effects of feces on marine environments and ecosystems.

• Journal of Drive and Control
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• v.10 no.2
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• pp.23-29
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• 2013

The excavator is used in a variety of construction environments. There are many kinds of risk like falling rocks or harmful dust. The excavator cabin protects the operator not only from these harmful environments but also provides a comfortable working environment. By the way, the excavator cabin consumes a lot of energy for cabin air conditioner. For this reason, the research is required to reduce energy consumption. This study suggests the air conditioning system for excavator using forced exhaust. First, the forced exhaust system simulated by AMESim tool and surveyed the applicability. Using AMESim simulation, it was investigated the effect of cabin inside temperature by intake flow rate and intake air temperature. The experiment executed using the 1.5 ton excavator and field tested according to the intake flow rate. Finally, verified the applicability on the air conditioning system for excavator using forced exhaust.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.5
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• pp.151-154
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• 2014

An energy of applications had consumed through the complexed inter-action with operating systems, run-time environments, compiler, and applications on various mobile devices. In these days, challenged researches are studying to reduce of energy consumptions that uses energy-oriented high-level and low-level compiler techniques on mobile devices. In this paper, we intented to reduce an energy consumption of Java mobile applications that applied a list instruction scheduling for energy dissipation from dalvik bytecode which extracted Android dex files. Through this works, we can construct the optimized power and energy environment on mobile devices with the limited power supply.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.9
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• pp.441-448
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• 2005

On-line dynamic security assessment is becoming more and more important for the stable operation of power systems as load level increases. The necessity is getting apparent under Electricity Market environments, as operation of power system is exposed to more various operating conditions. For on-line dynamic security assessment, fast transient stability analysis tool is required for contingency selection. The TEF(Transient Energy Function) method is a good candidate for this purpose. The clustering of critical generators is crucial for the precise and fast calculation of energy margin. In this paper, we propose a new method for fast decision of mode of instability by using stability indices. Case study shows very promising results.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.141-148
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• 2012

Ceiling cassette type air conditioner has been a main stream as a heating/cooling system recently in school, Korea. In this study, indoor thermal environments made by ceiling cassette type air conditioner were investigated by CFD simulation. Concentrations of $CO_2$ were investigated by a field measurement. Indoor thermal environment with the velocity inlet angle of $45^{\circ}$ from the ceiling in heating season was very ununiform so that thermal area was divided into two parts those the one is window side which is cold, and the other is corridor side which is hot. In cooling season under the same condition, there are areas too hot or too cold. If the velocity inlet angle is set in $30^{\circ}$ from the ceiling, indoor thermal environments was improved greatly in cooling season and heating season, too. Also, from the field measurement of $CO_2$ concentrations, it was suggested to install ventilators with proper air volume considered the number of class students.