• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.78-85
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• 2004

The new biotelemetry method and system that the installation and the treatment of equipment is convenient and the instantaneously detailed position of the fish attached a pinger is able to track comparatively easily had been developed, an practicality of it were verified in the water tank and the small sea port through the tracking of fish. The biotelemetry method had been gotten the three dimensional locations of fish to the receiving transducer by combining of the super short base line (SSBL) method to detect the direction of pinger and the pinger synchronizing method to measure the range from receiving transducer to pinger. The receiving system had been designed to realize the high precision or wide detection range by application of the basic design method for receiving system of biotelemetry and the hydrophone array configuration. From tracking test of carp in the water tank, the migration course and the velocity of carp was investigated and the observed migration course was compared with measurement. The measured migration course of carp coincided with the observation in the main and the position of carp was able to track three dimensionally. The velocity of carp measured by the moving average method was 11.2cm/s. From tracking test of yellowtail in the small sea port, the migration course and the velocity of yellowtail was investigated at natural condition. The position of yellowtail was able to track three dimensionally and the velocity of it measured by moving average method was 43.9cm/s.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.40.1-40.1
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• 2010

The Main payload of the STSAT-3 (Korea Science & Technology Satellite-3), MIRIS (Multipurpose Infra-Red Imaging System) has been developed for last 3 years by KASI, and its Flight Model (FM) is now being developed as the final stage. All optical lenses and the opto-mechanical components of the FM have been completely fabricated with slight modifications that have been made to some components based on the Engineering Qualification Model (EQM) performances. The components of the telescope have been assembled and the test results show its optical performances are acceptable for required specifications in visual wavelength (@633 nm) at room temperature. The ensuing focal plane integration and focus test will be made soon using the vacuum chamber. The MIRIS mechanical structure of the EQM has been modified to develop FM according to the performance and environment test results. The filter-wheel module in the cryostat was newly designed with Finite Element Analysis (FEM) in order to compensate for the vibration stress in the launching conditions. Surface finishing of all components were also modified to implement the thermal model for the passive cooling technique. The FM electronics design has been completed for final fabrication process. Some minor modifications of the electronics boards were made based on EQM test performances. The ground calibration tests of MIRIS FM will be made with the science grade Teledyne PICNIC IR-array.

• Journal of IKEEE
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• v.7 no.1 s.12
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• pp.9-15
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• 2003

An optimized finite-field multiplier is proposed for encryption and error correction devices. It is based on a modified Linear Feedback Shift Register (LFSR) which has lower power consumption and smaller area than prior LFSR-based finite-field multipliers. The proposed finite field multiplier for GF(2n) multiplies two n-bit polynomials using polynomial basis to produce $z(x)=a(x)^*b(x)$ mod p(x), where p(x) is a irreducible polynomial for the Galois Field. The LFSR based on a serial multiplication structure has less complex circuits than array structures and hybrid structures. It is efficient to use the LFSR structure for systems with limited area and power consumption. The prior finite-field multipliers need 3${\cdot}$m flip-flops for multiplication of m-bit polynomials. Consequently, they need 6${\cdot}$m latches because one flip-flop consists of two latches. The proposed finite-field multiplier requires only 4${\cdot}$m latches for m-bit multiplication, which results in 1/3 smaller area than the prior finite-field multipliers. As a result, it can be used effectively in encryption and error correction devices with low-power consumption and small area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.10
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• pp.758-765
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• 2018

This paper presents a 24-GHz frequency-modulated continuous wave(FMCW) radar transceiver with two Rx and one Tx channels in 65-nm complementary metal-oxide-semiconductor(CMOS) process and implemented it on a radar system using the developed transceiver chip. The transceiver chip includes a $14{\times}$ frequency multiplier, low-noise amplifier, down-conversion mixer, and power amplifier(PA). The transmitter achieves >10 dBm output power from 23.8 to 24.36 GHz and the phase noise is -97.3 GHz/Hz at a 1-MHz offset. The receiver achieves 25.2 dB conversion gain and output $P_{1dB}$ of -31.7 dBm. The transceiver consumes 295 mW of power and occupies an area of $1.63{\times}1.6mm^2$. The radar system is fabricated on a low-loss Duroid printed circuit board(PCB) stacked on the low-cost FR4 PCBs. The chip and antenna are placed on the Duroid PCB with interconnects and bias, gain blocks and FMCW signal-generating circuitry are mounted on the FR4 PCB. The transmit antenna is a $4{\times}4$ patch array with 14.76 dBi gain and receiving antennas are two $4{\times}2$ patch antennas with a gain of 11.77 dBi. The operation of the radar is evaluated and confirmed by detecting the range and azimuthal angle of the corner reflectors.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.263-270
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• 2003

Monte Carlo simulation has been peformed to induce optimized parameters of the detector head of gamma camera for the diagnosis of breast cancer and to evaluate it under the diagnosis condition of the breast cancer. For the simulation, we used Tungsten collimator, having a lattice structured array with holes of $3mm{\times}3mm$ and septal thickness of 0.25 mm, which are corresponding to the pixellated photosensor. For driving optimum parameters we used Trade-Offs procedure between the geometric efficiency and the spatial resolution, varying the detector head components. In order to pre-evaluate the performance of the optimized detector head, we assumed diagnosis condition that the breast tumor is located in the middle of phantom with various sizes and its location is 25 mm from the collimator surface, considering background count caused by radiation sources from other organs. It was shown that the performance of the optimized detector head can be degraded according to the breast cancer size and the background count under real diagnosis conditions of breast cancer. Therefore, it is concluded that the spatial resolution, which is used as an indicator to distinguish the various sizes of breast cancer and is dependent on the characteristic of the detector head, appears to be meaningless in early diagnosis of the breast cancer.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.419-424
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• 2016

In this paper, we studied a light distribution for the LED chips arrangement using an optical design software. The structures of the edge type LED luminaires are reflector plane, LGP(lighting guide plane) and diffuse plane. The reflector plane is on the middle of the overall structure. We had simulation that placing LED chips on the reflector center of the reflector edge by changing the position of LED chips above the reflector center at 1mm, 2mm, and 3mm respectively. In the case, when LED chips are on the center of the reflector, it shows the light distribution of the general diffuse illumination, the semi-direct distribution with 0.56 efficiency and the direct distribution with 0.31 efficiency. And the wedge type LGP shows more efficiency than the flat type. Gradually increasing shape of semi-spherical type by 0.015mm has power of 1.02W, efficiency of 0.25, and maximum luminous intensity of 0.104W/sr, it also and shows the better optical characteristics than the reflector plane that have no patterns. This semi-spherical type shows the better optical characteristics than the reflector plane that have no patterns.

• Journal of the Korean Geotechnical Society
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• v.28 no.8
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• pp.43-53
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• 2012

In the conventional design of a piled raft, the axial resistance offered by the raft itself is typically neglected and only that of the group pile is accounted in estimating the total axial resistance of the piled raft. As a consequence, piled rafts are usually designed conservatively by neglecting the raft resistance. In this study, a series of centrifuge model tests have been performed to compare the axial behavior of a group pile with that of a piled raft (both having 16 component piles with an array of $4{\times}4$) in sands with different relative densities and in clays with different preconsolidated pressures. The test results revealed that, with respect to the allowable settlement of 25 millimeters for bridge foundations, the piled raft resistances were greater than those of the group pile by 13% for dense sand, by 22% for loose sand, by 30% for stiff clay, and by 22% for soft clay. Furthermore, the ratio of piled raft resistance to group pile resistance increased as the settlement increased.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.383-388
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• 2007

A color filter was demonstrated incorporating a patterned metal grating in a quartz substrate. The filter is created in a metal layer perforated with a symmetric two-dimensional array of circular holes, with the pitch smaller than the wavelength of the visible light. A finite-difference time-domain simulation was performed to analyze the device by investigating the effect of structural parameters like the grating height, the period, the hole size, and the refractive index of the hole-filling material on its performance. The device performance was especially optimized by controlling the refractive index of the material comprising the holes of the grating. And two different devices were fabricated by means of the e-beam direct writing with the following design parameters: the grating height of 50 nm, the two pitches of 340 nm for the red color and 260 nm for the green color. For the prepared device with the period of 340 nm, the center wavelength was 680 nm and the peak transmission 57%. And for the other device with the pitch of 260 nm, the center wavelength was 550 nm and the peak transmission was 50%. The filling of the hole with a material whose refractive index is matched to that of the substrate has led to an increase of ${\sim}15%$ in the transmission efficiency.

• The KIPS Transactions:PartA
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• v.11A no.2
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• pp.115-122
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• 2004

In this paper, the multiple-valued adders and multipliers are implemented by current-mode CMOS. First, we implement the 3-valued T-gate and the 4-valued T-gate using current-mode CMOS which have an effective availability of integrated circuit design. Second we implement the circuits to be realized 2-variable 3-valued addition table and multiplication table over finite fields $GF(3^2)$, and 2-variable 4-valued addition table and multiplication table over finite fields $GF(4^2)$ with the multiple-valued T-gates. Finally, these operation circuits are simulated under $1.5\mutextrm{m}$ CMOS standard technology, $15\mutextrm{A}$ unit current, and 3.3V VDD voltage Spice. The simulation results have shown the satisfying current characteristics. The 3-valued adder and multiplier, and the 4-valued adder and multiplier implemented by current-mode CMOS is simple and regular for wire routing and possesses the property of modularity with cell array. Also, since it is expansible for the addition and multiplication of two polynomials in the finite field with very large m, it is suitable for VLSI implementation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.743-750
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• 2017

It is important to ensure a uniform temperature distribution in greenhouses for the mushroom cultivation. The air temperature of the mushroom cultivation greenhouse is made uniform by supplying a constant air temperature with the underground air. The mushroom cultivation array in a greenhouse in seven columns and four rows can make smooth air flows between the rows and prevent air differences between the top and bottom. The buoyancy effect in the entering air of 0.5m/s based on following density difference depending on initial internal temperature needs to be considered. The locations of the Fan Coil Unit (FCU) and fan were defined through flow analysis in a greenhouse to distribute the optimal uniform temperature. In this study, the air conditioning system of a greenhouse with a sandwich heat insulting panel shape which is composed of a FCU and fan was designed by flow analysis. A relatively uniform temperature distribution can be formed because the circulation path of air becomes longer in the different locations of the FCU (inlet) and fan (outlet) through the internal temperature and flow analysis. The cultivation and quality uniformity of the mushrooms could be promoted through these environmental improvements.