• Parasites, Hosts and Diseases
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• 제61권1호
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• pp.84-88
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• 2023

This study aimed to evaluate the positive rates for Enterobius vermicularis eggs among preschool children in Yeosu-si, Jeollanam-do, the Republic of Korea (Korea) over a period of 5 years (2017-2021). Perianal swab samples, obtained using cellotape, from 10,392 preschool children in 26 districts were examined microscopically for E. vermicularis eggs. The test results were notified through the local health center, and the families of children who tested positive were advised to provide them anthelmintics treatment. The annual positive rates were 5.0%, 5.2%, 4.4%, 2.2%, and 1.0% in 2017, 2018, 2019, 2020, and 2021, respectively. The overall positive rate was higher in boys than in girls (P< 0.05), and children aged 5-7 years were at a higher risk of being infected than those aged 0-4 years (P< 0.05). Although the rates of infection by E. vermicularis in the survey area, Yeosu-si, were still in the 1% range , the results of this study suggest that they can be significantly reduced through continuous intervention centered around the test-treatment strategy.

• 사상체질의학회지
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• 제24권4호
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• pp.62-74
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• 2012

Objectives : The purpose of this study is to investigate the effect of oral administration of Yongyukjowi-tang(YJT) on the immune activity in aged Sprague-Dawley rat(SD rat). Methods : SD rats were divided into three groups: Yongyukjowi-tang groups(YJT groups), distilled water groups(control groups) and Vitamin C groups(positive control groups) which were administered an oral dose(1ml/1day) to 6, 48 and 68 weeks old SD rats for four weeks. After four weeks, the number of total leukocyte, CD3+, CD4+, CD8+, and the level of cytokine (IL-2, IL-4, IL-10, IFN-${\gamma}$) were measured in spleen tissue of each SD rats. Results and Conclusions : 1) The number of total leukocyte significantly increased in 52 weeks old YJT group and 72 weeks old YJT group in comparison with those of the control group. 2) The number of CD3+ cell significantly increased in 72 weeks old YJT group in comparison with those of the control group and the positive control group. 3) The number of CD8+ cell significantly increased in 52 weeks old YJT group in comparison with those of the control group. 4) The level of IL-2 significantly increased in 72 weeks old YJT group in comparison with those of the control group and the positive control group. 5) The level of IL-4 significantly increased in 52 weeks old YJT group in comparison with those of the positive control group. These results suggest that oral administration of YJT has an effect on increase of immune activity in aged rat.

• Parasites, Hosts and Diseases
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• 제60권3호
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• pp.187-193
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• 2022

The positive rate of Clonorchis sinensis is the highest among intestinal parasites in the Republic of Korea (Korea). More than 1.2 million people were at risk of C. sinensis infection in Korea in 2012. An intensive control program is being implemented for residents of the 5 major river basins to reduce helminthic infections, including C. sinensis infection. This study evaluated the continuous intensive control program for parasitic diseases including clonorchiasis in areas near the 5 major river basins in Korea over the past 10 years (2011-2020). A total of 335,020 fecal samples (one sample per resident) prepared by the modified sedimentation technic were microscopically examined. Those who expelled helminth eggs were treated with anthelmintics through local health centers and re-examined 3 months later. The overall positive rate of helminths egg was 7.1%. The annual positive rates were dramatically decreased from 14.4% (2011) to 5.9% (2020). The egg positive rate was highest in C. sinensis (5.3%), followed by heterophyid flukes (1.5%) and Trichuris trichiura (0.2%). The prevalence of C. sinensis was significantly higher in males (7.6%) than in females (3.7%), and the highest in the 50-59 years (7.0%) age group. Our results are beneficial to establish prevention and control policies against helminthiases including clonorchiasis in endemic areas in this country.

• 충청수학회지
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• 제20권3호
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• pp.231-243
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• 2007

In this paper, we study a Lotka-Volterra type simple food chain model. We investigate the positive coexistence of the steady states to the model and give some results for the extinction of species under certain assumptions which can be interpreted as Domino effect and Biological control. The methods of a decoupling operator and the fixed point index theory on a positive cone are used as well as the comparison argument. Numerical evidences for our results also are provided.

• 한국어병학회지
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• 제37권1호
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• pp.147-153
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• 2024

The World Organization for Animal Health (WOAH) recommends two protocols (ITS and COI) for conventional PCR of G. salaris diagnosis. However, ITS PCR protocol may yield false-positive results, leading to unnecessary countermeasures. It's difficult to distinguish between G. salaris and false-positive by similar amplicon size of PCR, since the amplicon size of ITS PCR in G. salaris and false-positive was 1,300 and 1,187 bp, respectively. The nucleotide sequences of ITS false-positive in rainbow trout is 99.7% identical to previously reported host genome sequences of rainbow trout (Oncorhynchus mykiss) and 95.3 to 89.1% identical to those of other salmonid fish species. To reduce false-positive PCR band, PCR was performed by the different annealing temperature, but PCR bands were still detected. In RFLP analysis by HaeIII, the PCR product of G. salaris was digested into four bands of 512, 399, 234 and 154 bp, while the false-positive was digested into seven bands of 297, 263, 242, 144, 93, 80 and 68 bp. In the RFLP patterns digested by HindIII, G. salaris showed two bands of 659 and 640 bp, while false-positive had one fragment of 1,187 bp without any digestion. Therefore, the RFLP method of ITS PCR with HaeIII and HindIII can be used for differentiation between G. salaris and false-positive. These results might provide important information on the improvement of PCR diagnostic method of G. salaris.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.803-807
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• 2001

This paper presents a new control scheme for a DVR (Dynamic Voltage Restorer) system consisting of series voltage source PWM converters. To control the negative sequence components of the source, it is necessary to detect the negative sequence components. Generally, a filtering process is used which has some undesirable effects. This paper suggests a new method for separating positive and negative sequences components. This control system is designed using differential controllers and digital filters. The positive and negative sequences are extracted and controlled individually. The performance of the presented controller and scheme are confirmed through simulation and actual experiment with a 2.5kVA prototype DVR system.

• Asia Pacific Journal of Business Review
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• 제2권2호
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• pp.17-44
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• 2018

This study investigates whether the positive relation between the real earnings management (REM) and audit fees reported by Choi et al. (2016) differs before and after the Sarbanes-Oxley Act (SOX), and varies cross-sectionally depending on the existence of internal control problems. Using a large sample of U.S. firms, we find that the positive relation between REM and audit fees is stronger than the same relation between AEM and audit fees in the post-SOX period, whereas the opposite is true in the pre-SOX period. We also find that the positive relation between REM and audit fees is intensified for firms with material internal control weaknesses.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.143-144
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• 2016

The circulating current control within the phase legs is one of the main control objectives in a modular multilevel converter (MMC) under different operating conditions. This paper proposes a control strategy of circulating currents in the MMC under unbalanced voltage by using a proportional-resonant (PR) controller. Under the unbalanced voltage, the circulating currents in the MMC consists of three components such as positive-sequence, negative-sequence, and zero-sequence circulating currents. With the PR controller, all components of the circulating current will be directly controlled in the stationary reference frame without decomposing into positive- and negative-sequence components. Thus, the ripples in the circulating currents and the DC current are suppressed under the unbalanced voltage. The effectiveness of the proposed method is verified by simulation results based on PSCAD/EMTDC simulation program.

• 전력전자학회논문지
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• 제20권1호
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• pp.19-30
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• 2015

A static synchronous compensator (STATCOM) applied to rapidly changing, highly unbalanced loads such as electric arc furnaces (EAFs), requires both positive-sequence and negative-sequence current control, which indicates fast response characteristics and can be controlled independently. Furthermore, a delta-connected STATCOM with cascaded H-bridge configuration accompanying multiple separate DC-sides, should have high performance zero-sequence current control to suppress a phase-to-phase imbalance in DC-side voltages when compensating for unbalanced load. In this paper, actual EAF data is analyzed to reflect on the design of current controllers and a pioneering zero-sequence current controller with a superb transient performance is devised, which generates an imaginary -axis component from the presumed response of forwarded reference. Via simulation and experiments, the performance of the positive, negative, and zero-sequence current control of a cascaded H-bridge STATCOM for EAF is verified.

• 한국공작기계학회논문집
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• 제14권3호
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• pp.32-37
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• 2005

Several types of smart materials and control scheme are available to adjust the structure actively in various external disturbances. A control scheme was introduced for a specific material. But the effectiveness of the control scheme has some limitation according to the choice of the smart materials and the response of the structure. The ER(Electrorheological) fluid is adequate for a large control force, and the PZT(lead zirconate titanate) patches are suitable for small but arbitrary control force at any point of the structure. It can be used for active control of structure by changing the dynamic characteristics of the structure. But it has some difficulty in suppressing the excited vibration in broad band. To compensate this resonance of the controlled structure, a hybrid controller was constructed using PPF(Positive position feedback) control with PZT and ER fluid control.