• Journal of Korean Society of Transportation
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• v.21 no.5
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• pp.83-95
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• 2003

This study aims to develop travel time estimation and prediction models on the freeway using measurements from vehicle detectors. In this study, we established a travel time estimation model using traffic volume which is a principle factor of traffic flow changes by reviewing existing travel time estimation techniques. As a result of goodness of fit test. in the normal traffic condition over 70km/h, RMSEP(Root Mean Square Error Proportion) from travel speed is lower than the proposed model, but the proposed model produce more reliable travel times than the other one in the congestion. Therefore in cases of congestion the model uses the method of calculating the delay time from excess link volumes from the in- and outflow and the vehicle speeds from detectors in the traffic situation at a speed of over 70km/h. We also conducted short term prediction of Kalman Filtering to forecast traffic condition and more accurate travel times using statistical model The results of evaluation showed that the lag time occurred between predicted travel time and estimated travel time but the RMSEP values of predicted travel time to observations are as 1ow as that of estimation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.521-530
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• 2011

Since aircraft fuel tanks have many interfaces connected to the airframe as well as the fuel system, they have been considered as one of the system-dependent critical components. Crashworthy fuel tanks have been widely implemented to rotorcraft and rendered a great contribution for improving the survivability of crews and passengers. Since the embryonic stage of military rotorcraft history began, the US army has developed and practised a detailed military specification documenting the unique crashworthiness requirements for rotorcraft fuel tanks to prevent most, hopefully all, fatality due to post-crash fire. The mandatory crash impact test required by the relevant specification, MIL-DTL-27422D, has been recognized as a non-trivial mission and caused inevitable delay of a number of noticeable rotorcraft development programs such as that of V-22. The crash impact test itself takes a long-term preparation efforts together with costly fuel tank specimens. Thus a series of numerical simulations of the crash impact test with digital mock-ups is necessary even at the early design stage to minimize the possibility of trial-and-error with full-scale fuel tanks. In the present study the crash impact simulation of a few fuel tank configurations is conducted with the commercial package, Autodyn, and the resulting equivalent stresses and internal pressures are evaluated in detail to suggest a design improvement for the fuel tank configuration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.445-453
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• 2016

This paper presents the implementation and design of the 1T-1R wireless HD video streaming systems over 28 GHz mmWave frequency using 3GPP LTE-TDD standard on NI USRP RIO SDR platform. The baseband of the system uses USRP RIO that are stored in Xilinx Kintex-7 chip to implement LTE-TDD transceiver modem, the signal that are transceived from USRP RIO up or down converts to 28 GHz by using self-designed 28 GHz RF transceiver modules and it is finally communicated HD video data through self-designed $4{\times}8$ sub array antennas. It is that communication method between USRP RIO and Host PC use PCI express ${\times}4$ to minimize delay of data to transmit and receive. The implemented system show high error vector magnitude performance above 25.85 dBc and to transceive HD video in experiment environment anywhere.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.666-675
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• 2013

This research was carried out from March 2009 to July 2012 to explicate the height change based breeding-ecological characteristics of Titmice that were breeding in the artificial nests installed in the Halla Mountain. The first egg-laying day was delayed as the height of the area under investigation increased, and it turned out that the decrease in temperature due to the elevated height had influence on that delay (p<0.05). Generalizing the annual results of the analyses, we see that there was no significant correlation occurring between the average temperatures and egg-laying days in the breeding season (April~June) (p>0.05). The rate of artificial nest use was not different among areas and among year, but between the species, Parus major and Parus varius. There were differences in clutch sizes among species (p>0.05), but no differences in heights and years (p<0.05). The hatching-, fledging-, and breeding-success rates were 67.3%, 99.5%, and 67.0% respectively in 2011, and 71.3%, 96.8%, 69.0% respectively in 2012, from which we can tell that the fledging-success rate was high but the hatching- and breeding-success rates were similar. Though we confirm that temperature changes due to height differences had influence on breeding periods, but we cannot identify a significant correlation with other breeding-ecological characteristics. Thus, in order to more precisely explicate the influence of temperature changes due to heights on Titmice's breeding, long-term research is needed in terms of the investigation of microclimatic factors and food resource.

• Korean Security Journal
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• no.1
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• pp.283-319
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• 1997

Our society witnesses the rapid progress in the areas of politics, economy, society and culture in the process of national modernization since 1960s, which in turn as a reverse function gets to contract a societic pathology, totally lowering the security level of citizens' lives owing to various violent crimes like hostage commotions and murders with rifles and deadly weapons. what is the main reason for that? That may be partly because the chief police force concentrates on the current situation resulting in the vacuum of the public peace. However, the main reason is that the police fall short of man-power and equipments even if the whole police power were put to use in preventing and quelling the crimes. That is true not only of Korea but also of the advanced countries like the U.S.A., England and Japan. We realize that these advanced countries have higher level of security in every individual's life and property than Korea because their progress of the private guard systems can fill in a vacuum of the shortage of the police power, Therefore, we should without delay internationalize our private guard systems expecting the widely opening of the guard service markets in the age of Uruguay Round. To do this, we need to change our ideas for fostering the policy of the private guard from passive defense ideas into positive aggressive ones. Our police should urgently set up a plan to pursue the orientation of vision that we should dispatch our private guards overseas before foreign guards rush into our markets. Accordingly it goes without saying that the private guard group should distinguish their services from the public services initiating their own theory and strategy of private guard services and also readjust themselves between the public duties and the private services with the study of minimizing the reverse function of the private guard systems. The history criminal justice has always shown that the criminal system progressed at the initiative of the civil factor in case its demand and supply do not make both ends meet. Nevertheless, in the process the power of the government never weakens, rather it is built up in general. In conclusion, the necessity of the build-up of the private guard services must duly be acknowledged by the police as well as by the business which has its unique sphere within the criminal justice instead of as the suplemtary services of the simple the police power on the long-term basis. The purpose of the private guard services can be largely classified into the two categories; first it means the function to prevent the crimes against the citizens and secondly to enhance the national interest as an increasing mammoth business with a worldly competition capacity. The police has an absolute responsibility that they should protect the modem public in general from feeling the crisis of the personal threat, tension, anxiety and nervousness. In short, if we develop the complete private guard system to guarantee the societic atmosphere for all citizens, keep the public peace, and protect all citizens' lives and properties, we will sure enjoy a beautiful land, a wholesome society and a happy life in goodharmony of law and order.

• The Journal of Korean Medicine
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• v.32 no.2
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• pp.92-101
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• 2011

Purpose: To evaluate the effects on vision care program including traditional Korean treatment for elementary school students. Methods: 172 eyes of eighty-six older elementary students underwent a vision care program, including traditional Korean treatment, for 3 months between March 2010 and June 2010. The vision care program included health education, such as lifestyle modification, vision strengthening exercises and a course of treatment with traditional Korean methods. Traditional Korean treatment covered periocular acupuncture point stimulation, periauricular acupuncture point stimulation and herbal drug therapy. All patients were examined for visual acuity and auto-refraction and filled out a satisfactory questionnaire about ocular discomforts and quality of life before and after treatments. Results: Patients with mild myopia (-0.75~-2.00) were 61 (35.5%), and 46 (26.7%) were emetropia (${\pm}0.50$ or less). After treatment, uncorrected visual acuity in both eyes was $0.77{\pm}0.46$, which was lower than that before treatment ($0.82{\pm}0.51$), but corrected visual acuity was $0.98{\pm}0.21$, which was higher than that before treatment ($0.93{\pm}0.28 $). About the refractive change, the emetropia group showed a slightly myopic shift while the mild myopia group intended to reduce the myopic error. However, this was not statistically significant. The scales of eyeball pain or discomfort decreased significantly from $17.59{\pm}22.5$ before treatment to $10.28{\pm}17.80$ after treatment, and the scales of the quality of life increased from $1.85{\pm}1.25$ before treatment to $2.25{\pm}1.30$ after treatment. Most patients (90.7%) were satisfied with their treatment results. Conclusions: The vision care program including traditional Korean treatment for elementary school students was effective to improve corrected visual acuity in both eyes and delay the progression of school myopia. In addition, it helped to reduce eyeball pain and discomfort and ultimately to enhance quality of life. Long-term follow-up studies will be needed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.146-170
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• 2017

Joint channel assignment and routing is a well-known problem in multi-radio wireless mesh networks for which optimal configurations is required to optimize the overall throughput and fairness. However, other objectives need to be considered in order to provide a high quality service to network users when it deployed with high traffic dynamic. In this paper, we propose a re-configuration optimization model that optimizes the network throughput in addition to reducing the disruption to the mesh clients' traffic due to the re-configuration process. In this multi-objective optimization model, four objective functions are proposed to be minimized namely maximum link-channel utilization, network average contention, channel re-assignment cost, and re-routing cost. The latter two objectives focus on reducing the re-configuration overhead. This is to reduce the amount of disrupted traffic due to the channel switching and path re-routing resulted from applying the new configuration. In order to adapt to traffic dynamics in the network which might be caused by many factors i.e. users' mobility, a centralized heuristic re-configuration algorithm called State-Aware Joint Routing and Channel Assignment (SA-JRCA) is proposed in this research based on our re-configuration model. The proposed algorithm re-assigns channels to radios and re-configures flows' routes with aim of achieving a tradeoff between maximizing the network throughput and minimizing the re-configuration overhead. The ns-2 simulator is used as simulation tool and various metrics are evaluated. These metrics include channel-link utilization, channel re-assignment cost, re-routing cost, throughput, and delay. Simulation results show the good performance of SA-JRCA in term of packet delivery ratio, aggregated throughput and re-configuration overhead. It also shows higher stability to the traffic variation in comparison with other compared algorithms which suffer from performance degradation when high traffic dynamics is applied.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.1
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• pp.9-17
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• 2015

Glycogen storage disease (GSD) type Ia is rare inborn metabolic disorder, caused by glucose-6-phosphatase deficiency. It characterized by hepatomegaly, hypoglycemia, lactic acidosis, hypertriglyceridemia, and hyperuricemia and it is usually manifested in the infantile period. In addition, it is also associated with growth failure, pubertal delay, anemia, platelet dysfunction, osteopenia, and pulmonary hypertension. Hepatocellular adenoma and renal dysfunction are frequent late complications. Delayed diagnosis and inappropriate therapy lead to many complications such as growth failure, osteoporosis, refractory gout, renal failure, hepatocellular carcinoma (HCC), and pulmonary hypertension. Here, two Korean sisters diagnosed with GSD Ia, aged 33 and 36 respectively, were described and compared to recent articles about four adults with late diagnosis of GSD Ia. One sister had typical manifestations of GSD Ia including short stature (height, 145 cm), multiple hepatic adenoma, chronic kidney disease stage IV, and severe osteoporosis, whereas the older sister had normal stature (162 cm), one tiny hepatic nodule, and normal renal function. Direct sequencing of G6PC in two sisters identified a homozygous splicing mutation, c.645G>T, which is a prevalent mutation in Korea. Interestingly, our cases and four adults from recent reports had asymptomatic mild hypoglycemia and various manifestations including renal failure, HCC, fatty liver, or uncontrolled hyperlipidemia. These adult cases represent not only heterogenous phenotype to genotype within family members with GSD Ia but also long-term complications such as gouty arthritis, renal failure, and osteoporosis in untreated adult GSD Ia patients. In addition, lactic academia and hypertriglyceridemia are good markers of GSD Ia to distinguish from metabolic disease.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.170-175
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• 2016

In order to transmit baseband signals through frequency dividing devices, we studied the transfer function of the device in the term of the baseband signal distortion. From the analysis, it is shown that the magnitude of the envelope signal is related to the mixer gain and the insertion loss of the low pass filter whilst the phase is the additional function with the 1/2 of the phase delay. For the purpose of the verification of the study, we designed a dynamic frequency divider at 1,400 MHz. The operating frequency range of the device is closely related to the conversion gain of mixers and the amplitude of input signal, and becomes wide as the conversion gain of mixers increases. The designed frequency divider operates between 0.9 GHz and 3.2 GHz, for -14.5 dBm input power. The circuit shows 20 mW power dissipation at $V_{DD}=2.5V$, and the simulation result shows that an amplitude modulated signal at 1,400 MHz with the modulation index of 0.9 was successfully downconverted to 700 MHz.

• Sleep Medicine and Psychophysiology
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• v.11 no.1
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• pp.50-54
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• 2004

The obstructive sleep apnea syndrome can occur due to various etiologies in children. In otherwise healthy children, adenotonsillar hypertrophy is the leading cause of childhood obstuctive sleep apnea. Obstructive sleep apnea caused by adenotonsillar hypertrophy can lead to a variety of symptoms and sequelae such as behavioral disturbance, enuresis, failure to thrive, developmental delay, cor pulmonale, and hypertension. So if obstructive sleep apnea is clinically suspected, proper treatment should be administered to the patient after diagnostic examinations. More than 80% improvement is seen in symptoms of obstructive sleep apnea caused by adenotonsillar hypertrophy in children after tonsillectomy and adenoidectomy. However, when it is impossible to treat the patient using surgical methods or residual symptoms remained after tonsillectomy and adenoidectomy, additional treatments such as weight control, sleep position change, and continuous positive airway pressure (CPAP), should be considered. This paper reports a case using weight control and Auto-PAP to control mild sleep apnea and snoring, which in long-term follow-up were not resolved after tonsillectomy and adenoidectomy for severe obstructive sleep apnea.