• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.2
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• pp.108-116
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• 2002

In this paper, to improve bandwidth of microstrip antenna, we discussed the patch structure using dual patch and probe feed. To provide PCS service and IMT-2000 service simultaneous, a microstrip patch antenna needs impedance bandwidth of 22%. We propose wide-band microstrip path antenna without complexity. To analyze characteristics of microstrip patch antenna, we used Ensemble of commercial software. The microstrip patch antenna was designed, fabricated, and tuned. The result was that 500 ㎒(25.5%) of impedance bandwidth for VSWR 2,430 ㎒(21.9%) of impedance bandwidth for VSWR 1.5. The microstrip patch antenna has side lobe of -14 dB. The front to back ratio is 20 dB overall. The measured gain of the microstrip patch antenna is 5.2 dBi.

• The Research Journal of the Costume Culture
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• v.20 no.3
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• pp.403-415
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• 2012

This study did a comparative analysis on the patterns of several male bodice slopers, followed by evaluating the appearance through a virtual garment simulation, which used a three-dimensional virtual garment system. Through this process, this study attempted to comparatively analyze the suitability of the garment or each sloper according to body parts. The analysis of the drawing formulas of bodices slopers had the following results. With a standard chest size, all six slopers had a 1:4 ratio for a front and back chest size; 1:5 or 1:6 for a front and back breast size 1:5 or 1:4 for a neck base circumference; and 1:20 or 1:12 for the chest size. When comparing the anthropometric figures and the actual measurements of each body part for the bodice slopers, the actual measurements secured extra amounts in the drawing process. The evaluation results for appearance of the six men's bodice slopers showed that the slopers used by companies (E and F) had top scores followed by the slopers made for (C and D), while the sloper for education (A) received the lowest scores. Regarding the results of the variance analysis verifying the significant difference between the slopers, twenty-five items had significant differences with the exception of four items on the front side and one item on the backside.

• Korean Institute of Interior Design Journal
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• v.15 no.5 s.58
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• pp.120-129
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• 2006

Apartments have become the most popular type of residential building in Korea since the 1960s. The dwelling space should be designed to accomodate various life styles or changing needs of family members. This research is conducted to analyze flexible interior space types of apartments and to improve the architectural planning and design of apartments that can satisfy various needs of residents. In this study, apartments of 10 - 90 pyeongs built in the region of Seoul, between 1998 and 2007, are investigated in terms of the unit plan, the number of open sides, and a distribution of flexible apartment types for each year, Apartments with flexible space are classified into 10 different types, including a flexible type between bedrooms, a flexible type between a bedroom and the livingroom, and a flexible type between the dinning room and the livingroom. According to the composition of unit plans, apartments are also differentiated as a single-corridor type, a double-corridor type, a stairway type, a hall type, and a combination type. According to these classifications, the characteristics of desirable unit plans were analyzed. The results of the analysis showed that, as the unit size of apartments get bigger, the ratio of width/depth of the front side unit plan is increased. This result reflects a trend of high-rise apartments which have an increased number of front-side bays and a shorter depth for better penetration of daylight. In addition, a hall type is found to have a wider front side and shorter depth. According to open sides, a flexible type of the livingroom and the dinning room/kitchen (L-D.K) is found to be most common for the front/back open space, and the livingroom is usually placed on the front/side open space. To meet the changing needs of residents, more research should be conducted on flexible dwelling space.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.197-205
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• 2000

The back-off input power level method is generally used for design of high linear mixer. In this paper, the predistortive mixer design method which attaches the predistortor in front of mixer is proposed to compensate the nonlinear characteristics of mixer and the predistortor has inverse nonlinear characteristics of mixer. The proposed method improves C/I ratio of mixer by 22 dB (@Po=-20 dBm/tone), 21.7 dB(@Po=-17 dBm/tone) with two tones of RF at 1852.5MHz, 1857.5MHz and LO at 2015MHz, respectively.

• Journal of information and communication convergence engineering
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• v.16 no.4
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• pp.203-212
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• 2018

In this article, a novel design of patch antenna with wide band characteristics is presented. The proposed antenna is having electrical dimensions of $0.14{\lambda}{\times}0.11{\lambda}$ (at lower initial frequency) and footprints of $150mm^2$. Structural parameters optimization shows 3.1-23.5 GHz frequency range for a (reflection coefficient) $S_{11}{\leq}-10dB$ and simulated gain 6.8 dB is obtained. An equivalent circuit model is proposed to get an insight view of antenna. Advanced Systems Design (ADS) simulation results are obtain which confirm the validity of proposed model. Degenerated foster canonical form has been used to explain the reactance and capacitive behavior idea of simulated proposed antenna's input impedance later on an equivalent circuit model and smith chart is also suggested. HFSS and CST have been used to analyze antenna behavior. The proposed antenna can be further used for microwave image detection applications.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.387-392
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• 2003

This study is put a focus on the identification of sound characteristics according to the interior configuration of sound absorption material and air gap. Noise barrier is general consists of front perforated panel, air layer, sound absorption material, air gap and back plate. Noise barrier is required to the NRC value of 0.7. The absorbing performance of the noise barrier relies on the opening ratio of the perforated panel and the efficiency of the absorbing material. This study has observed the effect of opening ratio and hole size, the increase of sound absorbing performance by the configurations of sound absorption material and air gap. New designed noise barrier is achieved the acoustical performance of 0.87 the measurement in a reveration room.

• Fashion & Textile Research Journal
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• v.13 no.6
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• pp.934-942
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• 2011

This study was intended to analyze conventional grading increments and methods for middle-age men's pants, and to suggest new grading guidelines that will enable to improve satisfaction with size and silhouette as a result of combining the concept of grading, which help maintain the ratio and proportion by sizes as one of ready-made apparel's advantages, with body form oriented and aesthetic approaches. In the apparel industry, the current sizing specifications and methods adopted by relevant companies, as well as the characteristics of body forms of men aged 35 to 55 years were comparatively analyzed to find out problems and ultimately to suggest their solutions or improvements. It was considered that as the conventional grading practices used in the industry were customary on the basis of the past experiences, it was required to take the body forms of target consumers into account and also, to reconsider the conventional grading methods. Analyses of sizing and specifications by brands show that 4 to 19 sizes including 82 or 84 as standard size have been produced. Since men's apparel has a large number of sizes with the large range of sizes, grading is critically important. As silhouettes depend on the distribution of grading rule values at each point of increment pattern in the main regions during grading, it is necessary to consider both size grading and form variations. To maintain an appropriate silhouette with keeping the angle of center back line of a pattern, it is desirable to set the ratio of side line part to center part from the crease line to approximately 3:7. It is required to diversify the values of grading rules according to different sizes and pattern regions in consideration for the body forms of key consumers. In addition, if the natural lines of designs and patterns for the width increments of waist circumference and hip circumference, the increments of hip width in pant's front and back panels, the ratio of grading rule values of the right and left sides of crease line, knee circumference, thigh circumference and so on are taken into account, grading will be satisfactory in the all aspects of size, silhouette and ratio.

• The Journal of the Acoustical Society of Korea
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• v.10 no.5
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• pp.69-76
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• 1991

본 논문에서는 통계적 방법에 의한 음소의 자동분할에 관한 알고리즘을 제안하였다. 우선 음성 신호를 AR 모델로 모델링한 후 스펙트럼이 변화하기 전과 변화한 후의 모델에 대해서 likelihood ratio 와 mutual information을 고려한 test statistics 로부터 모델 계수가 변화하는 곳을 예측해 내고 이 곳을 음소의 경계로 판단한다. 이 경우 검파되지 못하는 대부분의 음소는 짧은 자음이었으며 Signed front-to-back maximum area ratio을 이용하여 개선하였다. 또한 false alarm error을 줄이기 위해 두 segment 사이의 distortion 으로부터 smoothing을 하였다. 3명의 화자에 대한 실험 결과 non-detection error는 10%, false alarm error는 20% 정도로 나타났지만 화자간에 알고리즘의 성능 변화가 거의 없으 며 특히 분할된 경계치 분포는 전체 음소의 90% 이상이 이 30ms 이내에 위치하였다.

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.115-119
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• 2022

A readout circuit for a mercury-cadmium-telluride (MCT)-amplified mid-wave infrared (IR) photodetector was realized and applied to noncontact chemical agent detectors based on a quantum cascade laser (QCL). The QCL emitted 250 times for each wavelength in 0.2-㎛ steps from 8 to 12 ㎛ with a frequency of 100 kHz and duty ratio of 10%. Because of the nonconstant QCL emission power during on-duty, averaging the photodetector signals is essential. Averaging can be performed in digital back-end processing through a high-speed analog-to-digital converter (ADC) or in analog front-end processing through an integrator circuit. In addition, it should be considered that the 250 IR data points should be completely transferred to a PC during each wavelength tuning period of the QCL. To average and minimize the IR data, we designed a readout circuit using the analog front-end processing method. The proposed readout circuit consisted of a switched-capacitor integrator, voltage level shifter, relatively low-speed analog-to-digital converter, and micro-control unit. We confirmed that the MCT photodetector signal according to the QCL source can be accurately read and transferred to the PC without omissions.

• Journal of the Korean Geotechnical Society
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• v.32 no.1
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• pp.5-18
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• 2016

In this study, we grasped the resistance state of the back ground which had a notable influence on computing the lateral resistance of the laterally loaded pile group in the homogeneous ground by the model test. Resistance state was grasped as the depth of rotation-point, wedge failure angle, and wedge wing angle. The model experiment is performed by varying the width, spacing and number of piles and the relative density of sand in this study. According to the observation of the rear ground surface deformation of the piles in lateral load, rotation point ratio, wedge failure angle, and wedge wing angle of the front row were similar to those of the middle row; however, those of the back row were relatively smaller. The rotation point ratio, wedge failure angle and wedge wing angle of the piles in parallel were the same as those of a single pile. Based on the model test results, equations for estimation of the rotation-point, wedge failure angle, and wedge wing angle are proposed.