• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.6 s.336
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• pp.67-74
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• 2005

In this paper, high LO-RF isolation W-band MIMIC single-balanced mixer was designed and fabricated using a branch line coupler and a $\lambda$/4 transmission line. The simulation results of the designed 94 GHz balun show return loss of -27.9 dB, coupling of -4.26 dB, and thru of -3.77 dB at 94 GHz, respectively. The isolation and phase difference were 23.5 dB and $180.2^{\circ}$ at 94 GHz. The W-band MIMIC single-balanced mixer was designed using the 0.1 $\mu$m InGaAs/InAlAs/GaAs Metamorphic HEMT diode. The fabricated MHEMT was obtained the cut-off frequency(fT) of 189 GHz and the maximum oscillation frequency(fmax) of 334 GHz. The designed MIMIC single-balanced mixer was fabricated using 0.1 $\mu$m MHEMT MIMIC Process. From the measurement, the conversion loss of the single-balanced mixer was 23.1 dB at an LO power of 10 dBm. Pl dB(1 dB compression point) of input and output were 10 dBm and -13.9 dBm respectively. The LO-RF isolations of single-balanced mixer was obtained 45.5 dB at 94.19 GHz. We obtained in this study a higher LO-RF isolation compared to some other balanced mixers in millimeter-wave frequencies.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.57-62
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• 2009

Purpose: Brain SPECT study is more sensitive to motion than other studies. Especially, when applying 1-day subtraction method for Diamox SPECT, it needs shorter study time in order to prevent reexamination. We were required to have new study condition and analysing method on dual detector system because triple head camera in Seoul National University Hospital is to be disposed. So we have tried to increase image quality and make the dual and triple head to have equivalent study time by using a new analysing program. Materials and Methods: Using IEC phantom, we estimated contrast, SNR and FWHM. In Hoffman 3D brain phantom which is similar with real brain, we were on the supposition that 5% of injected doses were distributed in brain tissue. To compare with existing FBP method, we used fan-beam collimator. And we applied 15 sec, 25 sec/frame for each SEPCT studies using LEHR and LEUHR. We used OSEM2D and Onco-flash3D reconstruction method and compared reconstruction methods between applied Gaussian post-filtering 5mm and not applied as well. Attenuation correction was applied by manual method. And we did Brain SPECT to patient injected 15 mCi of $^{99m}Tc$-HMPAO according to results of Phantom study. Lastly, technologist, MD, PhD estimated the results. Results: The study shows that reconstruction method by Flash3D is better than exiting FBP and OSEM2D when studied using IEC phantom. Flowing by estimation, when using Flash3D, both of 15 sec and 25 sec are needed postfiltering 5 mm. And 8 times are proper for subset 8 iteration in Flash3D. OSEM2D needs post-filtering. And it is proper that subset 4, iteration 8 times for 15sec and subset 8, iteration 12 times for 25sec. The study regarding to injected doses for a patient and study time, combination of input parameter-15 sec/frame, LEHR collimator, analysing program-Flash3D, subset 8, iteration 8times and Gaussian post-filtering 5mm is the most appropriate. On the other hands, it was not appropriate to apply LEUHR collimator to 1-day subtraction method of Diamox study because of lower sensitivity. Conclusions: We could prove that there was also an advantage of short study time effectiveness in Dual camera same as Triple gamma camera and get great result of alternation from existing fan-beam collimator to parallel collimator. In addition, resolution and contrast of new method was better than FBP method. And it could improve sensitivity and accuracy of image because lesser subjectivity was input than Metz filter of FBP. We expect better image quality and shorter study time of Brain SPECT on Dual detector system.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.105-110
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• 2010

Purpose: Three phase bone scan was considered sensitive in Patients with Reflex Symphathetic Dystrophy Syndrome (RSDS). Generally, three phase bone scan in the RSDS patients shows increased uptake of one side extremity joint. But three phase bone scan has been performed with flow, blood pool and delayed scan. We performed blood pool half body scan in order to investigate its usefulness. Materials and Methods: From October 2007 to September 2009, three phase bone scan (flow, blood pool, half body blood pool, delayed) was performed after injection of 750 MBq of $^{99m}Tc$-DPD in diagnosed patients with RSDS (M:F=8:7, R:L=9:6). For quantitative analysis, we obtained the count ratios of bilateral hands by drawing a region of interest (ROI) in the three phase images and compared with the count ratios of shoulders in half body blood pool and delayed images. Results: In flow images, right/left ratios were $1.09{\pm}0.53$. In blood pool images, right/left ratios were $1.13{\pm}0.47$ (hand), $1.08{\pm}0.26$ (shoulder). In delayed images, right/left ratios were $1.24{\pm}0.75$ (hand), $1.11{\pm}0.31$ (shoulder). As a result, Log of right/left counts of the others and that of shoulder blood pool image were correlated well with statistical significance (Spearman's R, p<0.005 SPSS for windows ver.12.0). Conclusion: Half body blood pool scan may be helpful in the diagnosis of patients with RSDS. Moreover, Half body blood pool scan reduced false negative and false positive rates. In order to improve agreement on interpretation of RSDS, Blood pool half body scan should be established as common criteria.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.93-97
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• 2009

Purpose: Recognize circulation work system and fixing work system's merits and demerits that is enforced in operation of PET/CT center in sudden increase recently. Wish to estimate connectivity degree of individual exposure dose and PET/CT working that is managed periodically through this and look for operation efficiency of PET/CT center. Materials and Methods: (1) Find interrelationship of length of service to be individual exposure dose and PET/CT through TLD interpretation. Specially, evaluate on the basis of data of 2.5 years until 2 quarters 2006~2008 year that show patient increase rapidly the latest. (2) Recognize what countermeasure is evaluating problems happened at circulation work system and fixing work system. Results: Patient examination's number was 14,674 items until 2 quarters 2006~2008 year, and the $^{18}F$-FDG average injection amount was 461.5 MBq. 2 people of 10 radiotechnologist did fixing work PET area and GAMMA area each, and 8 people did circulation work of 3 times for 2.5 years. Average exposure dose that PET area and Gamma area's circulation men in service receive was 1.32 mSv, and PET area men in services came out average 0.825 mSv high than Gamma area men in services. Nurse's exposure dose is 0.28 mSv, and next 2 reason is conjectured. One is contact with patient that medicate $^{18}F$-FDG injection, and another is consultation about patient's next time schedule after examination end. Although exposure dose's amount is not much, is expected to consider continuation work possibility by exposure dose in case is a nurse with pregnancy possibility. Also, $^{131}I$-isotope therapy area's radiotechnologist that use capsule appeared by 0.12 mSv and a nuclear medicine doctor appeared by exposure dose that is less of 0.11 mSv. Conclusions: In case do PET/CT center circulation work after a long time, connoted danger that most men in service is consecutiveness deficiency of business and individual exposure dose increase at early 1 month. Specially, way for individual exposure dose's decrease should be considered. Also, need to evaluate abhorrent work form for efficient work system introduction, and enforce circulation and fixing work suggestion suitable shift working. Finally, must make normalized business guide and so on to prevent circulation work people's business efficiency decline.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.160-168
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• 2008

Purpose: This study was designed to characterize the nutritional status and assess obesity to determine the relationship between obesity and serum lipid profiles in 6~7 year old children. Methods: In 2007, we surveyed 483 children (233 boys and 250 girls) aged 6~7 years. The total cholesterol, triglyceride levels and HDL-cholesterol were measured in the fasting state. Dietary information was obtained by a questionnaire. Results: The prevalence of obesity was 9.9%. There was no significant difference between genders. The mean caloric intake was 1,781 kcal in boys and 1,640 kcal in girls. The prevalence of excessive calories was 33% in boys and 30% in girls. The prevalence of a total cholesterol ${\geq}$200 mg/dL was 8.4%, TG ${\geq}$130 mg/dL was 5.0%, LDL-cholesterol ${\geq}$130 mg/dL was 3.1%, and HDL-cholesterol <35 mg/dL was 4.4%. The prevalence of hypertension was 2.1%. There was no significant difference between genders. The systolic blood pressure, triglyceride levels and LDL-cholesterol were significantly related to an increased obesity index (p<0.05). The mean caloric intake and nutritive component were not related to the obesity index. The obesity group was compared to the control group: for triglycerides ${\geq}$130 mg/dL the odds ratio was 4.08; for LDL-cholesterol ${\geq}$130 mg the odds ratio was 2.85; for a TC/HDL-cholesterol ${\geq}$4.0 the odds ratio was 1.16. The BMI and triglyceride levels in the group with hypertension were higher than control group (p<0.05). There were significant positive correlations between the BMI and blood pressure as well as the LDL-cholesterol and triglycerides (p<0.05). The BMI was not correlated with the mean caloric intake or nutrition. Conclusion: The prevalence of hypertension and hyperlipidemia in 6~7 year old children was significantly related to an increased obesity index. The management of obesity in 6~7 year old children should include a reduction in the risk for hyperlipidemia and hypertension.

• Journal of Korean Society of Transportation
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• v.22 no.3 s.74
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• pp.145-157
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• 2004

The cycle length design model of the Korean traffic responsive signal control systems is devised to vary a cycle length as a response to changes in traffic demand in real time by utilizing parameters specified by a system operator and such field information as degrees of saturation of through phases. Since no explicit guideline is provided to a system operator, the system tends to include ambiguity in terms of the system optimization. In addition, the cycle lengths produced by the existing model have yet been verified if they are comparable to the ones minimizing delay. This paper presents the studies conducted (1) to find shortcomings embedded in the existing model by comparing the cycle lengths produced by the model against the ones minimizing delay and (2) to propose a new direction to design a cycle length minimizing delay and excluding such operator oriented parameters. It was found from the study that the cycle lengths from the existing model fail to minimize delay and promote intersection operational conditions to be unsatisfied when traffic volume is low, due to the feature of the changed target operational volume-to-capacity ratio embedded in the model. The 64 different neural network based cycle length design models were developed based on simulation data surrogating field data. The CORSIM optimal cycle lengths minimizing delay were found through the COST software developed for the study. COST searches for the CORSIM optimal cycle length minimizing delay with a heuristic searching method, a hybrid genetic algorithm. Among 64 models, the best one producing cycle lengths close enough to the optimal was selected through statistical tests. It was found from the verification test that the best model designs a cycle length as similar pattern to the ones minimizing delay. The cycle lengths from the proposed model are comparable to the ones from TRANSYT-7F.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.119-129
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• 2004

This paper is designed to report the results of development and validation procedures in relation to the Freeway Incident Management System (FIMS) prototype development as part of Intelligent Transportation Systems Research and Development program. The central core of the FIMS is an integration of the component parts and the modular, but the integrated system for freeway management. The whole approach has been component-orientated, with a secondary emphasis being placed on the traffic characteristics at the sites. The first action taken during the development process was the selection of the required data for each components within the existing infrastructure of Korean freeway system. After through review and analysis of vehicle detection data, the pilot site led to the utilization of different technologies in relation to the specific needs and character of the implementation. This meant that the existing system was tested in a different configuration at different sections of freeway, thereby increasing the validity and scope of the overall findings. The incident detection module has been performed according to predefined system validation specifications. The system validation specifications have identified two component data collection and analysis patterns which were outlined in the validation specifications; the on-line and off-line testing procedural frameworks. The off-line testing was achieved using asynchronous analysis, commonly in conjunction with simulation of device input data to take full advantage of the opportunity to test and calibrate the incident detection algorithms focused on APID, DES, DELOS and McMaster. The simulation was done with the use of synchronous analysis, thereby providing a means for testing the incident detection module.

• Food Science of Animal Resources
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• v.29 no.1
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• pp.108-113
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• 2009

Apolipoprotein E (APOE) is a plasma lipoprotein in mammals and plays an important role in the transport and metabolism of lipids such as phospholipids and triglycerides. Therefore, the APOE gene could be a candidate gene controlling lipid metabolism in beef cattle. This study was performed to identify single nucleotide polymorphisms (SNP) in the APOE gene and to investigate the effects of SNP genotype on the carcass traits such as meat quantity and quality in Korean cattle. For PCR amplification, pooled DNA made from unrelated 60 individuals was prepared and primer pairs were designed based on the cDNA sequence of exon 4 region of the bovine APOE gene. A SNP was identified at position 2034 (T/C substitution) of the exon 4 region in the APOE gene. PCR-RFLP procedure with restriction enzyme ACC I was developed for determining the SNP genotype for each of a total of 309 animals with pedigree information and performance records through the national progeny testing program. The frequencies of the genotypes TT, TC and CC were 10.9, 46.9 and 42.2%. Gene frequencies were 0.344 for T allele and 0.656 for C allele. The g.2034T>C SNP genotype showed a significant effect (p<0.05) on dressing percentage and meat color, respectively. Animals with the TT genotype showed higher dressing percentage than those with the CC genotype, and TT genotype had desirable meat color compared with CC genotype. These results suggest that the g.2034T>C SNP genotype of the APOE gene may be useful as a DNA marker for meat quantity index and dressing percentage in Korean cattle.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.6-13
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• 2009

For X-band phased array systems, a power amplifier, a 6-bit phase shifter, a 6-bit digital attenuator, and a SPDT transmit/receive (T/R) switch are fabricated and measured. All circuits are demonstrated by using CMOS 0.18 um technology. The power amplifier has 2-stage differential and cascade structures. It provides 1-dB gain-compressed output power ($P_{1dB}$) of 20 dBm and power-added-efficiency (PAE) of 19 % at 8-11 GHz frequencies. The 6-bit phase shifter utilizes embedded switched filter structure which consists of nMOS transistors as a switch and meandered microstrip lines for desired inductances. It has $360^{\circ}$ phase-control range and $5.6^{\circ}$ phase resolution. At 8-11 GHz frequencies, it has RMS phase and amplitude errors are below $5^{\circ}$ and 0.8 dB, and insertion loss of $-15.7\;{\pm}\;1,1\;dB$. The 6-bit digital attenuator is comprised of embedded switched Pi-and T-type attenuators resistive networks and nMOS switches and employes compensation circuits for low insertion phase variation. It has max. attenuation of 31.5 dB and 0.5 dB amplitude resolution. Its RMS amplitude and phase errors are below 0.4 dB and $2^{\circ}$ at 8-11 GHz frequencies, and insertion loss is $-10.5\;{\pm}\;0.8\;dB$. The SPDT T/R switch has series and shunt transistor pairs on transmit and receive path, and only one inductance to reduce chip area. It shows insertion loss of -1.5 dB, return loss below -15 dB, and isolation about -30 dB. The fabricated chip areas are $1.28\;mm^2$, $1.9mm^2$, $0.34\;mm^2$, $0.02mm^2$, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.108-116
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• 2009

In this paper, we propose a Ethernet based audio distribution system with a new L1/L2 hybrid switching scheme, and evaluate its performance. The proposed scheme not only offers guaranteed low latency and jitter characteristics that are essentially required for the distribution of high-quality uncompressed audio traffic, and but also provide an efficient transmission of data traffic on the Ethernet environment. The audio distribution system with a proposed scheme consists of a master node and a number of relay nodes, and all nodes are mutually connected as a daisy-chain topology through up and downlinks. The master node generates an audio frame for each cycle of 125us, and the audio frame has 24 time slotted audio channels for carrying stereo 24 channels of 16-bit PCM sampled audio. On receiving the audio frame from its upstream node via the downlink, each intermediate node inserts its audio traffic to the reserved time slot for itself, then relays again to next node through its physical layer(L1) transmission - repeating. After reaching the end node, the audio frame is loopbacked through the uplink. On repeating through the uplink, each node makes a copy of audio slot that node has to receive, then play the audio. When the audio transmission is completed, each node works as a normal L2 switch, thus data frames are switched during the remaining period. For supporting this L1/L2 hybrid switching capability, we insert a glue logic for parsing and multiplexing audio and data frames at MII(Media Independent Interlace) between the physical and data link layers. The proposed scheme can provide a good delay performance and transmission efficiency than legacy Ethernet based audio distribution systems. For verifying the feasibility of the proposed L1/L2 hybrid switching scheme, we use OMNeT++ as a simulation tool with various parameters. From the simulation results, one can find that the proposed scheme can provides outstanding characteristics in terms of both jitter characteristic for audio traffic and transmission efficiency of data traffics.