• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.270-271
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• 2014

In spite of the methodology of evacuation process on vessels should be different comparing to the architecture on land, some have simulated the evacuations onboard ship with simulation tools which is developed only for the architecture. On this study, a vessel-oriented simulation tool is used to analyze the possibility of evacuation for a passenger ship. ${\cdots}$(중략)${\cdots}$ As a result of the simulation analysis, it is clear that the initial responding time and start-to-move time are so important, ${\cdots}$(중략)${\cdots}$.

• The Korean Journal of Zoology
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• v.35 no.1
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• pp.23-28
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• 1992

The effects of an antimetabolite, 6-aminonicotinamide (6-AU) on the levels of glucose, glycogen, catechoamines and mucleotides in mice brain were investigated. The level of glucose in the blood starts increasing from 3 h after administration of 6-AU while those in the brain tissue start increasing from 9 h after administration of 6-AN. The concentration of brain glvcogen remained unchanged at all time points except 11h. The level of epinephrine in the brain was found to reach maximum value at initial 3 h following 6-AU administration, after urhich it started dec$\ulcorner$easing si역서cantle. The Brvel of brain norepinephrine remained virtually unchanged before 24 h time point at which it starts decreasing significantly. ATP, CTP, UMP and UTP levels were significantly reduced but AMP and CMP levels urere not affected.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2313-2319
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• 2020

The goal of this project is to achieve an accurate segmentation of the pulmonary tumors besides shortening the time and increasing the accuracy. Here, improved region growing (IRG) algorithm is introduced in order to segment the lung tumor with a sufficient accuracy in a shorter time compared to the other basics methods. This comprehensive algorithm was applied on 4 patients CT images and the results of the various steps on segmentation improvement shown 98% accuracy as compared to the basic algorithm. The combination of "multipoint growth start" produced a desirable outcome in accurately bounding the tumor. The proposed algorithm improved tumor identification by less than 13% along with a sufficient percentage of compliance accuracy.

• Journal of Information Processing Systems
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• v.6 no.4
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• pp.575-596
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• 2010

Video-on-Demand services are increasing rapidly nowadays. The load on servers can be very high, even exceeding their capacity. For popular contents, we can use a Periodic Broadcast (PB) strategy using multicast to serve all clients. Recent development of PB uses multiple channels broadcasting for segments of movies in certain patterns, so that users only need to wait for a small segment to start the service. However, users need higher download capacity to download multiple segments at a time. In order to compensate for this, a proxy server can help to reduce download bandwidth requirements by holding some segments for a certain time. This research will focus on more recent PB schemes that couldn't be covered by previous Proxy-Assisted Periodic Broadcast strategies.

• IE interfaces
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• v.7 no.3
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• pp.171-180
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• 1994

Defined is a Multi-level Parallel Machine Flow-Shop (MPMFS) which reflects some real world manufacturing situations. Just-In-Time (JIT) philosophy is applied to the MPMFS scheduling in order to achieve lowering work-in-process inventory level as well as meeting due dates. A schedule generating simulator is developed. The latest start time of each operation is determined by a backward simulation followed by another forward simulation to analyze the schedule feasibility and actual inventory level. Reasonable schedules are available through adjusting some parameters for allowance factors such as set-up times of machines and other environmental changes. The SLAMSYSTEM under Window is employed for this processing with some input/output data handling processes devised under DOS.

• Journal of Integrative Natural Science
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• v.5 no.1
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• pp.13-17
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• 2012

Changes of Fabry-Perot fringe patterns in porous silicon during etching process has been investigated. Four porous silicon samples were prepared with four different etch currents: (a) 10 $mA/cm^2$, (b) 30 $mA/cm^2$, (c) 50 $mA/cm^2$, (d) 100 $mA/cm^2$, respectively. Optical characterization of Fabry-Perot fringe pattern on porous silicon was achieved by Ocean optics 2000 spectrometer. The change of Fabry-Perot fringes was monitored and measured during the etching process. Fabry-Perot fringes pattern start to form after couple of minutes. As the etching time increased, more reflection peaks were observed. Its full width at half maximum (FWHM) decreased rapidly when the etching time increased.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.73-81
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• 2007

We give two weaknesses of a recently proposed streamcipher MICKEY. We show time-memory-data tradeoff is applicable. We also show that the state update function reduces entropy of the internal state as it is iterated, resulting in keystreams that start out differently but become merged together towards the end.

• IE interfaces
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• v.22 no.1
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• pp.63-72
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• 2009

This paper considers a transporter scheduling problem under dynamic block transportation environment in shipbuilding. In dynamic situations, there exist the addition, cancellation or change of block transportation requirements, sudden breakdowns and maintenance of transporters. The transportation of the blocks in the shipyard has some distinct characteristics. Some blocks are available to be picked up at a specific time during the planning horizon while some other blocks need to be delivered before a specific time. These requirements cause two penalty times: 1) delay times incurred when a block is picked up after a required start time, and 2) tardy times incurred when a block shipment is completed after the required delivery time. The blocks are located at different areas in the shipyard and transported by transporters. The objective of this paper is to propose a heuristic algorithm based on a network flow model which minimize the weighted sum of empty transporter travel times, delay times, and tardy times. Also, a rolling-horizon scheduling method is proposed for dynamic block transportation environment. The performance of the proposed heuristic algorithms are evaluated through a simulation experiment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.7
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• pp.1792-1801
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• 2012

Symbol timing error amounts to a major degradation in the system performance. Conventionally, timing error is estimated by predefined preamble on both transmitter and receiver. The maximum of the correlation result is considered the start of the OFDM symbol. Problem arises when the prime path is not the strongest one. In this paper, we propose a new combined time and channel estimation method for multi-band OFDM ultra wide-band (MB-OFDM UWB) systems. It is assumed that a coarse timing has been obtained at a stage before the proposed scheme. Based on the coarse timing, search interval is set (or time candidates). Exploiting channel statistics that are assumed to be known by the receiver, we derive a maximum a posteriori estimate (MAP) of the channel impulse response. Based on this estimate, we discern for the timing error. Timing estimation performance is compared with the least squares (LS) channel estimate in terms of mean squared error (MSE). It is shown that the proposed timing scheme is lower in MSE than the LS method.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.212-219
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• 1998

Unburned hydrocarbon is a key contributor to both the fuel economy and emissions of automotive engine. Cyclic variation of HC emission is of importance, especially during throttle transients. The real time measurement of hydrocarbon is particularly important to obtain a better understanding of the mechanisms for combustion and emissions, especially during cold start and throttle transient condition. This paper reports the cycle resolved measurement technique of unburned hydrocarbons to quantify rapid changes of in-cylinder concentration in the vicinity of spark plug by using the Fast Response Flame Ionization Detector(FRFID). While this instrument actually measures fuel concentration, its results can be indicative of the AFR behaviour. In order to understand the rapid change of hydrocarbons with cylinder pressure, it is necessary to study the response time delay of the system, including the time associated with gas transportation to FID. And signal from FRFID is correlated with cylinder pressure data to relate changes in mixture preparation to the classic analysis, such as indicated mean effective(IMEF) and ignition delay, etc.