• Journal of Power Electronics
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• v.5 no.4
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• pp.312-318
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• 2005

This paper presents a compensator for reduction of the reactive lateral current in multiple autonomously controlled uninterruptible power supplies (UPS) connected in parallel. This compensator acts directly on the control equation for voltage amplitude and it provides an improved current distribution especially in the case of parallel connection of UPSs with different output power ratings. Observations show that the original control equation for output voltage amplitude is efficient for voltage regulation but it causes great variation of voltage levels. A compensator with the same structure is added to counterbalance the variation caused by the original control equation. Simulations show promising results with the employment of the proposed compensator. Our simulations are confirmed by experimental results using three UPSs with different output ratings and voltage limiters ($1\%$) connected in parallel under various conditions.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.88-95
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• 2002

본 연구에서는 균열 치유 거동을 가지는 소결된 Mullite/SiC의 모재, 열처리재, 균열재, 치유 균열재의 기계적 특성이 논의되었다. 반타원형 균열의 치수는 $100{\mu}m$ 과 $200{\mu}m$이다. 얻어진 결과는 다음과 같다. (a) Mullite/SiC 복합 세라믹스는 균열 치유 능력이 있었다. (b) 최적의 균열 치유 열처리 조건은 $1300^{\circ}C$, 1시간이었다. (c) 치유 가능한 최대 균열 길이는 직경 $100{\mu}m$의 반타원 균열이다. (d) 균열 치유부는 $1200^{\circ}C$이상에서 충분한 강도를 가졌고, 대부분의 시험편은 균열 치유부 이외의 영역에서 파단 하였다. (e) 공기중에서 예열처리는 본 재료의 피로강도 향상에 유용하였다.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.366-371
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• 1999

The volumetric curve was characterized by current functions of large amplitude and formation peak potential of adsorption oxygen (O(a)) was disappeared with sonication. The reduction peak potential of O(a) shifted about 0.05 V to noble direction in saturated $N_2$ and air systems with addition of $Cl^{-1}$ ion and sonication. The formation and ionization potentials of adsorption hydrogen (H(a)) had not been confirmed, and were not changed with sonication.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1998.12a
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• pp.537-545
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• 1998

This paper is the research about a joint coding system of source and channel coding using VF(Variable-to-fixed length) arithmetic code and BCH code. We propose a VF arithmetic coding method with EDC( Error Detecting Capability) and a joint coding method in that the VF arithmetic coding method with EDC is combined with BCH code. By combining both the VF arithmetic code with EDC and BCH code. the proposed joint coding method corrects a source codeword with t-errors in decoding of BCH code and carries out a improvement of the EDC of a codeword with more than (t＋1)-errors in decoding of the VF arithmetic coding with EDC. We examine the performance of the proposed method in terms of compression ratio and EDC.

• Advances in environmental research
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• v.7 no.3
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• pp.177-200
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• 2018

Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) in the surface water from the coastal areas of Bangladesh were analyzed by GC-MS/MS. Samples were collected in winter and summer, 2015. The total concentration of PAHs (${\Sigma}PAHs$) showed a slight variation in the two seasons, which varied from 855.4 to 9653.7 ng/L in winter and 679.4 to 12639.3 ng/L in summer, respectively. The levels of ${\Sigma}PAHs$ were comparable to or relatively higher than other coastal areas around the world. The areas with recent urbanization and industrialization (Chittagong, Cox's Bazar and Sundarbans) were more contaminated with PAHs than the unindustrialized area (Meghna Estuary). Generally, 2-3-ring PAHs were the dominant compounds. Molecular ratios suggested that PAHs in the study areas could be originated from both pyrogenic and petrogenic sources. The risk assessment revealed the extremely high ecological risk of PAHs, indicating an intense attention should be paid to PAHs pollution in the coastal areas of Bangladesh.

• Journal of the Korean Institute of Rural Architecture
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• v.26 no.1
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• pp.41-49
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• 2024

This study focuses on citizen-driven regional agenda and improvement projects, with a specific emphasis on the Yokohama Shimin Machi-bushin Project. The research aims to categorize the scope of citizens' thoughts and the objects for improvement, shedding light on the Analysis Methodologies of citizen-driven proposals for living environment improvement. It also highlights the diverse factors influencing citizens' perceptions of regional issues and the different approaches to addressing them. The paper discusses potential challenges and obstacles in implementing citizen-driven initiatives for community improvement and suggests ways to address them effectively. Overall, the study underscores the significance of citizen participation in community development and the need to understand their perspectives and thought processes in proposing and implementing community improvement initiatives.

• Clinical Endoscopy
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• v.55 no.1
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• pp.146-149
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• 2022

Lumboperitoneal or ventriculoperitoneal shunt insertion is a standard therapy for hydrocephalus that diverts cerebrospinal fluid from the subarachnoid space into the peritoneal cavity. Gastrointestinal perforations due to this procedure occur rarely; however, accepted treatment strategies have not yet been established. Hence, the most common treatment approaches are open surgery or spontaneous closure without endoscopy. We report the case of a small intestinal perforation in a 73-year-old-woman that occurred after the insertion of a lumboperitoneal shunt. A positive cerebrospinal fluid culture and high cerebrospinal fluid white blood cell count indicated a retrograde bacterial infection, and computed tomography revealed that the peritoneal tip of the shunt catheter was located in the lumen of the gastrointestinal tract. We repaired the perforation endoscopically using an over-the-scope clip, and the patient's recovery was uneventful. Use of an over-the-scope clip could be an effective and minimally invasive treatment for intestinal perforations caused by lumboperitoneal or ventriculoperitoneal shunt insertion.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.69.1-69
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• 2003

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.82-85
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• 1999

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.141-142
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• 1999