• Journal of Preventive Medicine and Public Health
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• v.39 no.2
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• pp.177-183
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• 2006

Objectives : In this study we examined the association between the genetic markers ACE (A-240T, C-93T, I/D, A2350G), AGT (M235T), AT1R (A1166C), CYP11B2 (T344C, V386A), REN (G2646A), ADRB2 (G46A, C79G, T47C, T1641), GNB3 (C825T) and ADD1 (G460W) and the presence of essential hypertension in adolescents. Methods : The Kangwha Study is an 18-year prospective study that is aimed at elucidating the determinants of the blood pressure level from childhood to early adulthood. For this study, we constructed a case-control dataset of size of 277 and 40 family trios data from the Kangwha Study. For this purpose, we perform a single locus-based case-control association study and a single locus-based TDT (transmission/disequilibrium test) study. Results : In the case-control study, the single locus-based association study indicated that the ADD1 (G460W) (p=0.0403), AGT (M235T) (p=0.0002), and REN (G2646A) (p=0.0101) markers were significantly associated with the risk of hypertension. These results were not confirmed on the TDT study. This study showed that genetic polymorphisms of the ADD1, AGT and REN genes might be related to the hypertension in Korean adolescents. Conclusions : This study provided useful information on genetics markers related to blood pressure. Further study will be needed to confirm the effect of the alpha adducin gene, the angiotensinogen gene and the renin gene on essential hypertension.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.1127-1135
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• 2014

Genome-wide association studies (GWAS) are designed to discover genetic variants such as single nucleotide polymorphisms (SNPs) that are associated with human complex traits. Although there is an increasing interest in the application of GWAS methodologies to population-based cohorts, many published GWAS have adopted a case-control design, which raise an issue related to a sampling bias of both case and control samples. Because of unequal selection probabilities between cases and controls, the samples are not representative of the population that they are purported to represent. Therefore, non-random sampling in case-control study can potentially lead to inconsistent and biased estimates of SNP-trait associations. In this paper, we proposed inverse-probability of sampling weights based on disease prevalence to eliminate a case-control sampling bias in estimation and testing for association between SNPs and quantitative traits. We apply the proposed method to a data from the Korea Association Resource project and show that the standard estimators applied to the weighted data yield unbiased estimates.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.139-145
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• 2007

The motion of single-rod cylinder is typically controlled by the directional control valve. In some case, the hydraulic system should be energized by the man power and at the same time the motion of a cylinder is controlled manually. It may be confusing for a man to do two things at the same time. The solution is to make up the closed hydraulic circuit with the bi-directional pump and single-rod cylinder without using a directional control valve. In the case of single-rod cylinder, the flows at the rod side and head side are so different that several valves should be installed to make the motion of single-rod cylinder possible. The hydraulic system is composed of a bi-directional pump, a single-rod cylinder, pilot operated check valves, a check valve and a counter balance valve for the purpose of actuating the lifter. The characteristics of a suggested system are analysized mathematically and numerically.

• 대한예방의학회:학술대회논문집
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• 2001.10a
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• pp.135-135
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• 2001

• Clinical and Experimental Reproductive Medicine
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• v.29 no.4
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• pp.259-267
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• 2002

Objective: This study was performed to compare the clinical outcomes of GnRH antagonist (Cetrorelix) single dose and multiple dose protocols for controlled ovarian hyperstimulation with GnRH agonist long protocol. Materials and Method: From September 2001 to March 2002, 48 patients (55 cycles) were performed controlled ovarian hyperstimulation for ART using by either GnRH antagonist and GnRH agonist. Single dose of 3 mg GnRH antagonist was administered in 15 patients (17 cycles, single dose group) at MCD #8 and multiple dose of 0.25 mg of GnRH antagonist was administered in 15 patients (18 cycles, multiple dose group) from MCD #7 to hCG injection day. GnRH agonist was administered in 18 patients (20 cycles, control group) by conventional GnRH agonist long protocol. We compared the implantation rate, number of embryos, and clinical pregnancy rate among three groups. Student-t test and Chi-square were used to determine statistical significance. Statistical significance was defined as p<0.05. Results: There were no significant differences in ampules of used gonadotropins, number of mature oocytes, obtained embryos between single and multiple dose group, but compared with control group, ampules of used gonadotropins, number of mature oocytes, obtained embryos were decreased significantly in both groups. Clinical pregnancy rate and implantation rate were not different in three groups. There were no premature LH surge and ovarian hyperstimulation syndrome in three groups. Multiple pregnancy were occurred 1 case in multiple dose group and 2 case in control group. Conclusions: GnRH antagonist is a safe, effective, and alternative method in the controlled ovarian hyperstimulation compared with GnRH agonist. Clinical outcomes and efficacy of both single and multiple dose protocol are similar between two groups.

• 전기의세계
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• v.26 no.2
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• pp.99-103
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• 1977

The object of this work is to study an optimal design problem of the proportional load-frequency controller for the single-control area power system. The selfservice power station is still a popular means as a power supplying source on ships or in a certain manufacturing area. The power system of this kind can be formulated as a single control-area system and it attracts a certain academic interest in controlling the system frequency under disturbances. In this paper, the single control-area system is mathematically formulated as a linear, time-invariant system in state-space under certain assumptions. The optimal proportional control law and the realization of the controller in closed loop-version is studied so that the final system designed can attain the system frequency to the nominal stationing value after the small load-disturbance. As in general cases of optimal design problems, the performance index is assumed to be quadratic in states and the control effort, and the infinite time control process is assumed in this work. The final control system realized depicts certain improvements in case study; in stability, transient responses and in steady-state frequency deviation, even though the steady state error did not attain the zero value.

• Journal of Drive and Control
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• v.14 no.4
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• pp.17-22
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• 2017

In this study, the back-drivability of the single-rod and double-rod type EHAs (Electro-Hydrostatic Actuators) was compared by computer simulation and experiments. The back-drivability of EHAs exhibit non-linear behavior like their force tracking performance. In case of the double-rod type EHA, the back-drivability was mostly influenced by the bulk modulus of oil that changes with the working pressure due to entrapped air. The back-drivability of the single-rod type EHA was directly affected by the operation states of its pilot-operated check valves, while the asymmetrical piston geometry and the non-linear bulk modulus of oil also made the dynamic response in building up the cylinder pressure dependent on the operating conditions.

• Journal of Drive and Control
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• v.14 no.4
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• pp.9-16
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• 2017

In this study, the force tracking performance of the single-rod and double-rod type EHAs (Electro-Hydrostatic Actuators) was compared by computer simulation and experiments. The force-controlled EHAs exhibit non-linear behavior that are significantly dependent on operation conditions. The investigation focused on localizing the parameters that provide significant rise to the non-linearity. For this, the single-rod and double-rod type EHAs were mathematically expressed to derive their linear models. In parallel, they were modeled by a commercial simulation program including non-linear properties based on experimental results. It was shown that the dependency of the bulk modulus of oil with entrapped air on working pressure dominated the non-linearity in force control performance in case of the double-rod type EHA. The force control of the single-rod type EHA was influenced by much more elements. Besides the asymmetrical piston geometry and the non-linear bulk modulus of oil, its pilot-operated check valves made it dependent not only on the magnitude of reference input but also on its direction.

• PNF and Movement
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• v.13 no.4
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• pp.203-213
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• 2015

Purpose: Deficits in lower-extremity function and trunk control ability have a negative impact on individuals with hemiplegia. This case report aimed to describe the effect of trunk stability exercises using proprioceptive neuromuscular facilitation (PNF) on trunk control ability, balance, and gait in a patient with hemiplegia. Methods: A 77-year-old man with hemiplegia and trunk and lower extremity impairment participated in this four-week training intervention. Results: The patient demonstrated improvements in trunk control ability, balance, and gait performance. Outcome measures (Fugl-Meyer Assessment Lower Extremity (FMA-LE), Trunk Control Test, Berg Balance Scale, Timed Up and Go test, 10 Meter Walk test) were measured before and after the training program. Conclusion: The results of this case suggest that a trunk stability exercise using a PNF program may improve trunk control ability, balance, and gait in a patient with hemiplegia.

• Fire Science and Engineering
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• v.31 no.2
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• pp.24-28
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• 2017

This study compared the performance of a smoke control system in the case of a fire with that in the case of non-fire. Single-pressurization in the vestibule, single-pressurization in the stairwell, simultaneous smoke control of the stairwell and vestibule, which was the pressurization of smoke control, were assessed. The result showed that simultaneous smoke control of the stairwell and vestibule can maintain the differential pressure and is least influenced for the evacuation of evacuees. In addition, for the status of smoke control in Korea and the proper pressurization method, these results highlight the necessity of improving the current pressurization method through the survey.