• Journal of Korea Water Resources Association
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• v.49 no.5
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• pp.431-438
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• 2016

Large energy consumption is one of the main weaknesses of RO desalination. A new method is proposed to reduce the energy consumption of RO desalination which depends on the salinity of the feedwater. Low salinity feedwater can be obtained using groundwater wells which extracts both fresh groundwater and subsurface sea water. Subsurface feedwater is advantageous in overcoming other problems associated with surface seawater intakes. Salinities of groundwater depend on a number of factors. In this work a new simulation-optimization model is proposed to identify well locations and pumping rates with would provide the required design flow rate with the minimum salinity. When groundwater is developed in a coastal area, the saltwater wedge advances inland and may contaminate existing groundwater wells, which must be prevented. The model can protect existing wells while developing minimum salinity feedwater. Examples are provided to demonstrate the usage of the model.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.688-694
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• 1999

Ti-6Al-4V-N films have been grown onto glass substrates by dc reactive magnetron sputtering from a Ti-6Al-4V-N alloy target at different nitrogen partial pressure, input powers and sputtering times. The influence of various sputtering conditions on structural properties of Ti-6Al-4V-N films was investigated by measuring their X-ray diffraction. The quaternary Ti-6Al-4V-N film is crystallizing in a face centered cubic TiN structure, the lattice parameter is smaller than the TiN parameter as titanium atoms of the TiN lattice are replaced by aluminum and vanadium atoms. The films show the (111) preferred orientation and the (111) peak intensity decreases as the nitrogen partial pressure is increased, but the intensity increases as the sputtering time is increased. The deposition rate and the grain size are alto related with the variation of various sputtering conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.93-95
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• 2013

The conventional assistive tool for visually impaired people provide Simple service using a ultrasound, or an RFID tag to identify the obstacles. It is impossible to clear guide and has a vulnerability to unforeseen circumstances because of short recognition distance, The ARM Cortex-A9 Platform based implementation of the Portable Navigation System and Service Center will help the visually impaired gait. The Service Center will also provide solution for the lack of jobs due to the increase of the aging population. Navigation System that the visually impaired can carry possessing devices such as a camera, GPS, Audio, Ethernet transmit Image shown at the location of the visually impaired, GPS information and Sound Via TCP / IP. The staff of the service center receives information and can provide directions by communicating with them. So, the system can provide effective guidance to the visually impaired.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.142-149
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• 2004

PMLSM(Permanent Magnet linear Synchronous Motor) has widely applied to industrial automations, machine tools and semiconductor equipments due to the merit on the reduction of noise, vibration and the superior dynamic characteristics in comparison to the conventional method, which uses mechanical transfer equipments. Especially, in the case of applying to Z-axis operation structure, control system needs the method of an initial angle setting and the improvement of up/down operation characteristics. This paper proposes an initial angle setting algorithm and a variable gain schedule using real speed and moving direction to improve up/down operation characteristics. The effectiveness of proposed algorithms Is demonstrated by comparing to a conventional gain system via 4-point absolute positions profile with each velocity, acceleration and deceleration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.437-440
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• 2007

Recently embedded system developed a lot. Physically, embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants. This paper focuses on implementation of portable device which is applicable to the child-kidnap or missing child prevention system in residential area or public area. To be specific, this device is to transmit video data which comes from the camera in the device into the host PC via WLAN. Embedded hardware platform consists of s3c2440 with ARM9 core, WindowsCE OS and other sensors. OS enables the platform to do multitasking jobs which are handling GPS data, taking video, capturing audio via microphone in the device and transfer all kind of realtime data to the host PC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.735-744
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• 2016

This study attempted quantitative analysis by space syntax on the plan of a non-hierarchical arrangement, which selected SANAA's work after Almere Stadt Theater, and analyzed the difference in the quantitative value of the non-hierarchical arrangement in plan that appears externally. The analysis results were as follows. First, SANAA's spaces with a non-hierarchical arrangement plan that appears externally showed a definite quantitative value difference, and had a hierarchical space difference in the plan that does not appear externally. Second, the spaces with a high integration value also had a high connectivity value, which is indicated by increasing the number of space openings using the method of giving hierarchy to the non-hierarchical arrangement plan or adjusting the size of the room or location to grant hidden hierarchy. Third, SANAA used exterior corridor rather than interior corridor in grid-type plan to solve the accessibility problem, and the open coat spaces between rooms provide natural lighting and ventilation and are used as equipment that controls the hidden hierarchy of space at the same time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4302-4307
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• 2011

Recently, various technologies for the fuel efficiency improvement are being developed. The purpose of this study is to evaluate the heat exchanging performance of a exhaust heat recirculation device and to propose a model with optimized performance. The device has been designed to warm up engine coolant as quickly as possible using wasted exhaust heat. To achieve these goals, heat transfer characteristics has been analyzed using CFD for the flow direction effect and in/out location effect of coolant. A method improving the effectiveness of heat exchange has been proposed. As a result, the highest efficiency in heat exchange was observed on condition that exhaust heat affects the coolant directly with a separate flow path between exhaust gas and coolant and that coolant flow rate is relatively low.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.451-462
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• 2009

Recently, there are many active studies to enhance low I/O performance of hard disk device. The studies on the hardware make good progress whereas those of the system software to enhance I/O performance may not support the hardware performance due to its poor progress. In this paper, we propose a new method of prefetching n-blocks into the flash memory. The proposed method consists of three steps: (1)analyzing the pattern of read requests in block units; (2)determining the number of blocks prefetched to flash memory; (3)replacing blocks according to block replacement policy. The proposed method can reduce the latency time of hard disk and optimize the power consumption of the computer system. Experimental results show that the proposed dynamic n-block method provides better average response time than that of the existing AMP(Adaptive multi stream prefetching) method by 9.05% and reduces the average power consumption than that of the existing AMP method by 11.11%.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.51-55
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• 2002

This study was to investigate the effect of EEG wave type of visual cortex on conjugate movement of eyeball according to movement of visual target. Visual evoked potential(VEP) system used the Bio-Pag(production in USA) and recorded to 586 computer. The illumination of test room was 50lux and the visual target was red light dot of 3cm size. The results of dextroversion and levoversion as follows : The visual stimulation waves on the visual cortex have about 71% of delta wave, about 12% of beta wave, about 9% theta wave and about 6% of alpha wave respectively. The dextroversion and levoversion state was similar results on the histogram amplitude of EEG wave, frequency of EEG wave type, EEG wave style and phase diagram of amplitude. Expecially the histogram amplitude of EEG wave appeared almost the Gaussian shape and the phase analysis of amplitude of EEG wave was nearly linear shape. On the fast fourier transform of the amplitude and Hz, the frequency was almost low frequency under 20 Hz, and the dextroversion and levoversion shape was similar results.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.235-240
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• 2017

Recently, Internet of things have been applied to various fields and are becoming common in our everyday life. Everything in our daily lives is networked, interacting with each other and giving us more useful effects. In this paper, we implemented an algorithm that can illuminate the LED lighting to the authorized person 's place in the network environment connected with the authentication device only once with the user authentication. User authentication in one building User authenticated through a single user search for the location of the user's lab stored in the database using the certified information and LED lights up to the lab where the user works. Through this, unnecessary energy is generated because people do not pass frequently.