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Reduction of Spreading Thermal Resistance Using Vapor Chamber Heat Pipe
You-Seop Lee(이유섭),Jongseok Kim(김종석) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
This paper studies heat spreading aspect of a vapor chamber for chip cooling application. The vapor chamber is a flat-plate heat pipe which can be embedded in the base of a heat sink to reduce the spreading thermal resistance. The thermal behavior of the vapor chamber with acetone as working fluid and micro grooves for wick structure has been experimentally investigated. The employment of the vapor chamber could make the junction temperature of the chip decrease up to 10 K with a reduction of spreading thermal resistance of 0.4 K/W. Such a thermal spreading effect depends on the area ratio of the vapor chamber and heating element. A spreading thermal resistance analysis is performed using Lee's closed form correlation to estimate the spreading capability of the vapor chamber. The thermal behavior of the vapor chamber is also numerically studied using in a good agreement with the junction temperature measurement results.
Feline Demographics and Disease Distribution in the Republic of Korea
Jongseok Lee,Son-il Pak,Kija Lee,Ho-jung Choi,Young-Won Lee,In-chul Park,최수영 한국임상수의학회 2022 한국임상수의학회지 Vol.39 No.5
The population of pet cats has increased significantly, from 0.3% in 2002 to 5.6% in 2017. Large-scale feline demographic and disease data from Korea are lacking. The aim of this study was to investigate the demographic data (breed, sex, and age) and disease distribution of cats who visited private veterinary practices in Korea. Data including breed, sex, age, and disease, were compiled from 32,728 electronic medical records from 30 selected private vet- erinary practices, between January 1, 2016, and December 31, 2017. Diseases were classified based on the International Classification of Diseases 11 by the World Health Organization, and then compared and cross-analyzed according to breed, sex, and age. Korean shorthair was the most common breed. There was a high distribution of young cats, with 77.6% of the cats under 4 years of age, and an average age of 2.5 years. Diagnoses related to preventative medicine were the most frequent and diagnoses common to young cats had higher incidence. This demographic data and information about disease distribution can be used as a basis for future research and may be helpful for determining priorities in the diagnosis of diseases and establishing strategies for health management in cats.
Jongseok Lee,Sungok Jang,Haemin Jeong,Ohk-Hyun Ryu 대한내과학회 2020 The Korean Journal of Internal Medicine Vol.35 No.1
Background/Aims: The aim of this study is to compare Friedewald-estimated and directly measured low density lipoprotein cholesterol (LDL-C) values and assess the concordance in guideline risk classification between the two methods. Methods: The data were derived from the 2009 to 2011 Korea National Health and Nutrition Examination Survey. We included subjects with triglyceride (TG) levels < 400 mg/dL. Analysis was done for 6,454 subjects who had all lipid panels— total cholesterol, directly measured LDL-C, high density lipoprotein cholesterol (HDL-C), and TG. Results: The subjects ranged in age from 10 to 87 years old. The mean age was 41.5 ± 17.3 years. For subjects with TG < 400 mg/dL, overall concordance in guideline risk classification was 79.1%. The Friedewald formula tended to underestimate LDL-C more at higher TG or lower HDL-C levels. Especially, the percent of subjects who were misclassified into a lower risk category was 31% when TG were 200 to 299 mg/dL; and 45.6% when TG were 300 to 399 mg/dL. A greater underestimation of LDL-C occurred at higher TG and lower Friedewald-estimated LDL-C levels. Of subjects with a Friedewald-estimated LDL-C < 70 mg/dL, 55.4% had a directly measured LDL-C ≥ 70 mg/dL when TG were 200 to 399 mg/dL. Conclusions: The Friedewald equation tends to underestimate LDL-C in highrisk subjects such as hypertriglyceridemia and hypo-HDL-cholesterolemia. For these individuals accurate assessment of LDL-C is crucial, and therefore additional evaluation is warranted.
Lee, Jongseok,Armstrong, Derek T.,Ssengooba, Willy,Park, Jeong-ae,Yu, Yeuni,Mumbowa, Francis,Namaganda, Carolyn,Mboowa, Gerald,Nakayita, Germine,Armakovitch, Sandra,Chien, Gina,Cho, Sang-Nae,Via, Laur American Society for Microbiology 2014 Antimicrobial Agents and Chemotherapy Vol.58 No.1
<P>For <I>Mycobacterium tuberculosis</I>, phenotypic methods for drug susceptibility testing of second-line drugs are poorly standardized and technically challenging. The Sensititre MYCOTB MIC plate (MYCOTB) is a microtiter plate containing lyophilized antibiotics and configured for determination of MICs to first- and second-line antituberculosis drugs. To evaluate the performance of MYCOTB for <I>M. tuberculosis</I> drug susceptibility testing using the Middlebrook 7H10 agar proportion method (APM) as the comparator, we conducted a two-site study using archived <I>M. tuberculosis</I> isolates from Uganda and the Republic of Korea. Thawed isolates were subcultured, and dilutions were inoculated into MYCOTB wells and onto 7H10 agar. MYCOTB results were read at days 7, 10, 14, and 21; APM results were read at 21 days. A total of 222 isolates provided results on both platforms. By APM, 106/222 (47.7%) of isolates were resistant to at least isoniazid and rifampin. Agreement between MYCOTB and APM with respect to susceptibility or resistance was ≥92% for 7 of 12 drugs when a strict definition was used and ≥96% for 10 of 12 drugs when agreement was defined by allowing a ± one-well range of dilutions around the APM critical concentration. For ethambutol, agreement was 80% to 81%. For moxifloxacin, agreement was 83% to 85%; incorporating existing DNA sequencing information for discrepant analysis raised agreement to 91% to 96%. For MYCOTB, the median time to plate interpretation was 10 days and interreader agreement was ≥95% for all drugs. MYCOTB provided reliable results for <I>M. tuberculosis</I> susceptibility testing of first- and second-line drugs except ethambutol, and results were available sooner than those determined by APM.</P>
Compression of 3D Mesh Geometry and Vertex Attributes for Mobile Graphics
Jongseok Lee,Sungyul Choe,Seungyong Lee 한국정보과학회 2010 Journal of Computing Science and Engineering Vol.4 No.3
This paper presents a compression scheme for mesh geometry, which is suitable for mobile graphics. The main focus is to enable real-time decoding of compressed vertex positions while providing reasonable compression ratios. Our scheme is based on local quantization of vertex positions with mesh partitioning. To prevent visual seams along the partitioning boundaries, we constrain the locally quantized cells of all mesh partitions to have the same size and aligned local axes. We propose a mesh partitioning algorithm to minimize the size of locally quantized cells, which relates to the distortion of a restored mesh. Vertex coordinates are stored in main memory and transmitted to graphics hardware for rendering in the quantized form, saving memory space and system bus bandwidth. Decoding operation is combined with model geometry transformation, and the only overhead to restore vertex positions is one matrix multiplication for each mesh partition. In our experiments, a 32-bit floating point vertex coordinate is quantized into an 8-bit integer, which is the smallest data size supported in a mobile graphics library. With this setting, the distortions of the restored meshes are comparable to 11-bit global quantization of vertex coordinates. We also apply the proposed approach to compression of vertex attributes, such as vertex normals and texture coordinates, and show that gains similar to vertex geometry can be obtained through local quantization with mesh partitioning.
Lee, Hwiseob,Lim, Wonseob,Lee, Wooseok,Kang, Hyunuk,Bae, Jongseok,Park, Cheon-Seok,Hwang, Keum Cheol,Lee, Kang-Yoon,Yang, Youngoo IEEE 2017 IEEE microwave and wireless components letters Vol.27 No.3
<P>This letter presents a compact load network for Doherty power amplifier (DPA) integrated circuits (ICs) using p-type left-handed (LH) and right-handed (RH) transmission lines (TLs) based on lumped components. The quarter-wave impedance transformers based on the LH TLs and a compensation method for the internal shunt capacitance using a shunt inductor were adopted for the impedance matching networks. The p-type LH and RH TLs for the matching networks and a combining network can be further simplified by merging adjacent shunt components. In order to verify the proposed load network, a 2.6-GHz DPA IC was designed and fabricated using a 0.4-mu m gallium nitride high-electron-mobility transistor process for small-cell base stations. The overall size of the chip is 1.7 x 1.8 mm(2) and the chip was mounted on a quad flat no-leads package. For a long term evolution signal with a signal bandwidth of 10 MHz and a peak-to-average power ratio of 6.5 dB, a high drain efficiency of 52.2% was obtained at an average output power of 34.0 dBm.</P>
A Fast Image Stitching Algorithm in The Endless Hot Rolling Process
JongSeok Lee,NamWoong Kong,JinWoo Yoo,PooGyeon Park 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
Camber is one of the most important defects in the endless hot-rolling process, and can be defined as the longitudinal curvature of a slab or strip in the plan view. To obtain a value of the camber for a steel bar, the overall shape of a slab or strip is required. However, the strip is too long to capture overall image at once. In order to obtain precise information on the overall shape of the bar, two area-scan charge-coupled device (CCD) cameras to obtain partial bar images and the image stitching algorithm are needed. This paper proposes a fast algorithm to obtain the overall shape of a steel bar in the endless hot rolling process. The proposed algorithm reduces the computational complexity and the running time of the image stitching process by adaptively selecting the search region to find feature points in steel bar images. The algorithm consists of three parts: generating the feature points and descriptors of the selected regions of continuous images for the steel bar, choosing the overlapped region between the present image and the next image, and stitching the partial bar images after calibrating them. The proposed stitching algorithm based on adaptive selection of the search region improves the performance of the camber measurement system during the image stitching process.