• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.835-842
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• 2004

In this paper, we have analyzed the MC-DS/CDMA system with input signal synchronized completely through adjustment of the gain in the PLL loop, by using the hybrid SC/MRC-(2/3) technique, which is said to one of the optimal diversity techniques under the multi-path fading environment, assuming that phase error is defined to the phase difference between the received signal from the multi-path and the reference signal in the PLL of the receiver. Also, assuming that the regarded radio channel model for the mobile communication is subject to the Nakagami-m fading channel, we have developed the expressions and performed the simulation under the consideration of various factor, in the MC/DS-CDMA system with the hybrid SC.MRC-(2/3) diversity method, such as the Nakagami fading index(m), $the\;number\;of\;paths\;(L_p),$ the number of hybrid SC.MRC-(2/3) $diversity\;branches\;(L,\;L_c),$ the number of users (K), the number of subcarriers (U), and the gain in the PLL loop. As a result of the simulation, it has been confirmed that the performance improvement of the system can be achieved by adjusting properly the PLL loop in order for the MC/DS-CDMA system with the hybrid SC/MRC-(2/3) diversity method to receive a fully synchronized signal. And the value of the gain in the PLL loop should exceed 7dB in order for the system to receive the signal with prefect synchronization, even though there might be a slight difference according to the values of the fading index and the spread processing gain of the subcarrier.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.932-940
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• 1999

Object-oriented programming is often touted as promoting software reuse. However it is recognized that objected-oriented software often need to be restructured before it can be reused. refactoring is the process that changes the software structure to make it more reusable, easier to maintain and easire to be enhanced wit new functionalities. This paper desirbes experience gained and lessons learned from restructuring OODesigner, a Computer Aided Software Engineering(CASE) tool that supports Objects Modeling Technique(OMT). this tool supports a wide range of features such as constructing object modeler of OMT, managing information repository, documenting class resources, automatical generating C++ and java code, reverse engineering of C++ and Java cod, searching and reusing classes in the corresponding repository and collecting metrics data. although the version 1.x was developed using OMT(i.e the tool has been designed using OMT) and C++, we recognized that the potential maintenance problem originated from the ill-designed class architecture. Thus this version was totally restructured, resulting in a new version that is easier to maintain than the old version. In this paper, we briefly describe its restructuring process, emphasizing the fact that the Refactoring of the tool is conducted using the tool itself. Then we discuss lessons learned from these processes and we exhibit some comparative measurements of the developed version.

• The Journal of Korean Academy of Prosthodontics
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• v.19 no.1
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• pp.17-27
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• 1981

This study was conducted to determine the chemical composition and the mechanical properties of four commercially available low gold-based crown and bridge alloy produced in Korea. Four dental casting gold-silver-palladium alloys, i.e., A, B, C and D (code of alloys) were selected for the evaluation of chemical composition, ultimate tensile strength, elongation. values and Vickers hardness. The chemical composition of test specimens was analyzed by both emission spectrography and wet gravitation method with a 1.5gm of low gold ingot. The tensile properties and Vickers hardness was determined with cast specimens treated in following three conditions; as-cast, softening heat treatment and hardening heat treatment. The tensile testing bars were cast in accordance with the model designed by Gettleman and Harrison (1969) which was modified from the A. D. A. Specification No. 14 for dental chromium-cobalt casting alloy. Nine tensile test specimens were made from a split silicone mold for each of the test alloys to the size of 2.5mm in diameter and a gauge length of 10mm. All four alloys were handled in accordance with conventional methods used in Type III gold alloys. Ultimate tensile strength and elongation were measured on an Instron Universal Tensile Testing Machine (Model 1125, Japan) operated at a crosshead rate of 0.1cm/min. Elongation values were measured using Digital Measuring Microscope (MS-152, FUSOH, Japan). Vickers hardness was determined with a Vickers Hardness Tester (Model VKH-l, Japan) at a 1.0kg load on a mounted tensile test specimen. The following results were obtained from this study; 1. All tested alloys were composed of Au, Ag, Pd, Cu, Zn and Fe in common. The composition rate of gold for all four alloys was found in the range of $42{\sim}47$ weight % as shown below. Alloy A; Au 45%, Ag 40.2%, Pd 5.76%, others 9.04%. Alloy B; Au 47.1%, Ag 29.03%, Pd 6.98%, others 16.92%. Alloy C; Au 45%, .Ag 26.9%, Pd 6.83%, others 21.07%. Alloy D; Au 41.8%, Ag 34.4%, Pd 6.95%, others 16.85%. 3. The ultimate tensile strength of the four alloys was in the range of $31{\sim}82kg/mm^2$. The test results were shown in the below order from the highest value; As-cast condition; D, B, C, A. Softening heat treament; B, C, D, A. Hardening heat treatment; D, B, C, A. 4. The test :results of the elongation rate for each alloy were in the range of $0.5{\sim}18%$. The test results were shown in the below order from the highest value; As-cast condition; A, D, B, C. Softening heat treatment; A, C, D, B. Hardening heat treatment; C, D, B, A. 5. Vickers hardness for each of the four alloys was in the range of $120{\sim}230$. The test results were shown in the below order from the highest value; As-cast condition; C, B, D, A Softening heat treatment; D, B, C, A. Hardening heat treatment; D, A, C, B. 6. There were no differences in the physical properties between as-cast condition and softening heat treatment.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.370-393
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• 2015

This study was conducted to compare STQ method, multi-residue method in Korean food code and QuEChERS method for validated selected and accuracy, reproducibility and efficiency. A total of 45 selected and targeted pesticides were the analyzed by GC and 5 of them were crops (apple, potato, green pepper, rice, soy bean). $R^2$ values were calculated in the standard calibration curve was over 0.990. Recovery tests were performed by three replications in two levels and the relative standard deviation of the repeated experiments was less than 30%. The average percentage of recoveries in the multi-residue method in Korean food code was 89.13%, QuEChERS method was 92.45% and STQ method was 85.28%. In addition, matrix effects in multi-residue method in Korean food code was 24.61%, QuEChERS method was 23.98% and STQ method showed 11.24%. The STQ method is easy and showed high clean-up effect in extracting the sample solution than the QuEChERS method and clean-up with C18, PLS, PSA cartridge columns. A large volume of the sample was injected in order to compensable for the problem, that occurred due to high detection limit in the analyser. When the STQ method was applied using a large volume injector, the standard calibration curve showed a higher linearity $R^2=0.990$, and method detection limit was 0.01 mg/kg. It showed an average recovery of 91.84% and the relative standard deviations of three replications repeated in two level process was less than 30% and had an average matrix effect of 17.90%.

• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.662-669
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• 2010

To develop the manufacturing methods for the blanket first wall (FW) of the International Thermonuclear Experimental Reactor (ITER) and to verify the integrity of the joint, Be/Cu mockups were fabricated and tested at the KoHLT-1 (Korea Heat Load Test facility), a graphite heater facility located at the Korea Atomic Energy Research Institute (KAERI). Since Be and Cu joining is the focus of the present study, the fabricated mockups had a CuCrZr heat sink joined with three Be tiles as an armor material, unlike the original ITER blanket FW, which has a stainless steel structure and coolant tubes. Hot isostatic pressing (HIP) was carried out at $580^{\circ}C$ and 100 MPa for 2 hours as the method for Be/Cu joining. Three interlayers, namely, $1{\mu}mCr/10{\mu}mCu$, $1{\mu}mTi/0.5{\mu}mCr/10{\mu}mCu$, and $5{\mu}mTi/10{\mu}mCu$ were applied as a coating to the Be tiles by a physical vapor deposition (PVD) method. A shear test was performed with the specimens, which were fabricated by the same methods as those used to fabricate the mockups. The average values were 125 MPa to 180 MPa, and the samples with the $1{\mu}mCr/10{\mu}mCu$ interlayer showed the lowest value. No defect or delamination was found in the joints of the mockups by the developed ultrasonic test using a flat-type probe with a 10 MHz frequency and a 0.25 inch diameter. High heat flux (HHF) tests were performed at $1.0\;MW/m^2$ heat flux for each mockup using the given conditions, and the results were analyzed by ANSYS-CFX code. For the test criteria, an expected fatigue lifetime about 1,000 cycles was obtained by analysis with ANSYS-mechanical code. Mockups using the interlayers of $1{\mu}mTi/0.5{\mu}mCr/10{\mu}mCu$ and $5{\mu}mTi/10{\mu}mCu$ survived up to 1,100 cycles over the required number of cycles. However, one of the Be tiles in the other two mockups using the $1{\mu}mCr/10{\mu}mCu$ interlayer was detached during the screening test, and others were detached by discharge after 862 cycles. The integrity of the joints using the proposed interlayers was proven by the HHF test, but the other interlayer requires more study before it can be used for the joining of Be to Cu. Moreover, it was confirmed that the measured temperatures agreed well with the analysis temperatures, which were used to estimate the lifetime and that the developed facility showed its capability of the long time operation.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1656-1662
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• 2013

The ternary phase $EuZn_xIn_{4-x}$ has been identified as the main product of reactions of Eu, Zn, and In by using the In-flux method and characterized by both powder and single-crystal X-ray diffraction. The structure belongs to the common $BaAl_4$-type (tetragonal space group I4/mmm, Pearson code tI10) with lattice parameters of a = 4.5610(9) ${\AA}$, c = 12.049(3) ${\AA}$ for composition $EuZn_{1.10(12)}In_{2.90}$ and a = 4.5463(3) ${\AA}$, c = 12.028(2) ${\AA}$ for composition $EuZn_{1.18(2)}In_{2.82}$, respectively. In this structure, the Eu atoms are situated at the center of 18-vertex Fedorov polyhedra made of Zn and In atoms, where the 4d site is preferentially occupied by In and the 4e site is occupied by randomly mixed Zn and In atoms. Theoretical investigations using tight-binding linear muffintin orbital (TB-LMTO) method provide rationale for the observed site preferences and suggest potentially wider homogeneity range than the experimentally established for $EuZn_xIn_{4-x}$ ($x{\approx}1.1$).

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.545-552
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• 2010

In this paper, we study on a radio multiple sensing interface module to accurately decide serious error sources that are happened by unexpectable problems in industrial fields, in addition, we study a reliability improvement scheme to guarantee the integrity of multiple sensing data. For multiple sensing interface module, communication drivers such as USART, TWI, ADC and GPIO-I2C are implemented. to improve the transmission reliability, reed-Solomon code is used. From the simulation result of this system in indoor environment, we confirm that the reliability of RS coded data is improved about 5 times than uncoded data. Moreover, we prove that multiple sensing interface module is suitable to diagnose error sources of industrial automaton equipment.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.17-28
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• 2015

The applications program that running on Operating System has high dependence. Because environment of OS and standard libraries that supports are different. For those reason, Applications that perform the same function should be implemented in accordance with the new operating system. This results in a temporal and economic waste not only in subsequent maintenance of application but also in management. Even though, to solve this problem Cygwin or MinGW has been distributed, they do not support the portability of the application but provide a virtual environment and the tool. Therefore, in this paper, we design the wrapper format interface middleware using the POSIX and standard C library to support the application performing the same function on virtual environment and without code modification. The middleware can be selectively loading the API that is classified by basic and extend. This allows to managing the application size efficiently. Also, perform the comparative experiments and performance evaluation for application, on equipped with the Interface Middleware Linux, Unix, Windows and on Cygwin.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.655-662
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• 2013

This study was carried out to investigate the changes in the quality properties of red pepper Yukwa (red pepper liquid fermented with lactic acid bacteria was added to the Yukwa) during the storage period. To determine the shelf life of red pepper Yukwa, the rice Yukwa (control) and red pepper Yukwa were stored at 15, 25, and $35^{\circ}C$ for 70 days. Also, the quality properties of red pepper Yukwa, such as acid value, peroxide value, texture, color, and sensory evaluation were measured. Although the acid value of rice Yukwa and red pepper Yukwa increased during storage, the red pepper Yukwa showed a lower acid value score (1.09mg KOH/g) than that (1.19mg KOH/g) of the rice Yukwa. Nevertheless, these values did not exceed the guideline maximum values of 2.0 g KOH/g specified in the Korean Food Code. The peroxide values of samples had significantly increased after 42 days. Especially, the peroxide value scores for the rice Yukwa and red pepper Yukwa were the highest at 146.49 and 126.79 meq/kg at $35^{\circ}C$, respectively. Hardness and brittleness in textural properties increased up to 70 days. The sensory values for the red pepper Yukwa for overall acceptance, taste;texture and appearance were the highest. The results indicated that by using the 'Visual Shelf life Simulator for foods' of the Korea Food and Drug Administration (KFDA) the shelf life of red pepper Yukwa is estimated to be 274.78 days.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.6
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• pp.20-29
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• 1998

This paper proposes the algorithms that design the highly parallel multiple-valued logic curcuit and assign the code to each node of DCG(Directed Cyclic Graph) of length 1. The conventional Nakajima's algorithm have some problems, so this paper introduce the matrix equation from DCG of length 1 and proposes circuit design algorithms according to the DCG of length 1. Using the proposed circuit design algorithms in this paper, it become realized that was not able to design from Nakajima's algorithm. Also, making a comparision between the circuit design using Nakajima's algorithm and this paper's, we testify that proposed paper's algorithm is able to realize more optimized circuit design. According to proposed curcuit design algorithm in this paper, it is possible to design curcuit that DCG have natural number, so it have the following advantages; reduction of the curcuit input/output digits, simplification of curcuit composition, reduction of computation time and cost. And we show compatibility and verification about this paper's algorithm.