• Journal of Korean Society of Forest Science
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• 제76권2호
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• pp.169-177
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• 1987

The concept of multiple-use forestry can be considered as a simple application of the economic theory which commands the efficient utilization of resources. This paper reviews two important branches of the economic theory-theory of the firm and the capital theory-and discusses various methodologies of measuring the non-timber benefits from the forest. In addition, an empirical analysis with an example of the Deogyu National Park is presented. For this purpose, the Clawson's Travel Cost Method was employed.

• Journal of Practical Engineering Education
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• 제14권2호
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• pp.327-332
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• 2022

This experiment presents a precise analysis method using a mass spectrometer in the biopharmaceutical market, where utility is expanding. Among various techniques for analyzing the protein drug, somatotropin, the peptide fragments through biochemical sample preparation was analyzed by LC-MS/MS characterization. The analysis process was performed by separation analysis using nanoUPLC and MS/MS analysis using Orbitrap. In the case of somatotropin with 21 tryptic peptides, 13 of them were consistent with theoretical predictions within an average of 1 ppm error.

• Journal of Korean Society of Environmental Engineers
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• 제38권6호
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• pp.334-342
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• 2016

Conventional eco-design has been implemented based only on the environmental aspects of a product. Key components of a product identified from the analysis of the environmental aspects have been the target for improvement in the conventional eco-design. The use of eco-design index (EDI) considering both the environmental and economic aspects, and utility value (UV) of a product can be envisaged as an alternative way of implementing and assessing the eco-design. The objective of this study was to propose the logic of the EDI and apply it to the components for performing printing function of the multi-function printer. The EDI was formulated by quantifying the UV, life cycle environmental impact (LCE) and life cycle cost (LCC) of the components of a product, here components of the printer. Of the eight components investigated, roller was identified as the best performing consumable in both the environmental and economic aspects. However, its UV was the lowest among the eight. The EDI of the roller was mere $4^{th}$ in ranking out of the eight. Transfer belt ranked $8^{th}$ and $5^{th}$ in the environmental and economic aspects, respectively, while $2^{nd}$ in the utility value with its EDI ranked $3^{rd}$. This indicates that not only the environmental aspects but also economic and utility value aspects should be considered when identifying the key components for improvement in the eco-design.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.147-147
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• 2017

$TiO_2$는 의료기기, 광촉매, 태양전지 등의 여러 분야에 응용이 가능하여 많은 연구가 진행되어 왔다. 그 중 양극산화를 통하여 수직으로 잘 정렬된 나노튜브는 넓은 반응면적, 높은 전자 전도성 등의 장점으로 그 성능을 더욱 향상 시킬 수 있어 많은 연구자들이 이용하고 있다. 양극산화의 특성상 Ti 기판 위에 형성된 나노튜브의 효용성을 높이기 위하여 기판에서 분리하여 membrane의 형태로 이용하기도 한다. 이런 $TiO_2$ 나노튜브 멤브레인의 이용은 주로 오염물의 분해를 위한 광촉매, 염료감응 태양전지의 전극으로 이용되고 있다. 본 연구는 $TiO_2$ 나노튜브 멤브레인에 기체 동위 원소 분리에 이용되는 HKUST-1, ZIF-8 등과 같은 Metal Organic Frame Work (MOF)을 충진 시켜 극저온에서 수소 동위 원소를 분리 하고 자 하는데 있다. 하지만 MOF를 충진하기 위해서는 기존의 $TiO_2$ 나노 튜브 멤브레인보다 더 넓은 내경과 안정성이 요구되는 바이다. 이를 위하여 본 연구에서는 내경을 수백 나노미터 이상으로 확장하기 위한 전해질, 전류(전압) 조건 등에 대하여 연구 하였다. 또한 멤브레인의 안정적인 제조를 위하여 2-step 양극산화 조건, 열처리 조건 등의 변화를 통하여 그 목적을 달성 하고자 하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제21권2호
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• pp.73-78
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• 2021

To minimize the resonance frequency error when design Inset-Fed Microstrip Patch Antenna using current formulas. Especially It is found that a constant relation between Antenna patch width and frequency error. Using this relation, calculation frequency and simulation frequency are compared. Finally the comparison induced a formula of revised antenna patch width for accurate frequency in 2-10 GHz. And this formula reduced 2.54% of average frequency error. Last, the Antenna which has same variation with the simulation was producted and measured. It proved the formula's validity.

• Journal of KIISE:Databases
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• 제28권2호
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• pp.217-232
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• 2001

본 논문에서는 시계열 데이터베이스에서 정규화 변환을 지원하는 서브시퀀스 매칭 알고리즘을 제안한다. 정규화 변환을 시계열 데이터 간의 절대적인 유클리드 거리에 관계 없이, 구성하는 값들의 상대적인 변화 추이가 유사한 패턴을 갖는 시계열 데이터를 검색하는 데에 유용하다. 기존의 서브시퀀스 매칭 알고리즘을 확장 없이 정규화 변환 서브시퀀스 매칭에 단순히 응용할 경우, 질의 결과로 반환되어야 할 서부시퀀스를 모두 찾아내지 못하는 착오 기각이 발생한다. 또한, 정규화 변환을 지원하는 기존의 전체 매칭 알고리즘의 경우, 모든 가능한 질의 시퀀스 길이 각각에 대하여 하나씩의 인덱스를 생성하여야 하므로, 저장 공간 및 데이터 시퀀스 삽입/삭제의 부담이 매우 심각하다. 본 논문에서는 인덱스 보간법을 이용하여 문제를 해결한다. 인덱스 보간법은 인덱스가 요구되는 모든 경우 중에서 적당한 간격의 일부에 대해서만 생성된 인덱스를 이용하며, 인덱스가 필요한 모든 경우에 대한 탐색을 수행하는 기법이다. 제안된 알고리즘은 몇 개의 질의 시퀀스 길이에 대해서만 각각 인덱스를 생성한 후, 이를 이용하여 모든 가능한 길이의 질의 시퀀스에 대해서 탐색을 수행한다. 이때, 착오 기각이 발생하지 않음을 증명한다. 제안된 알고리즘은 질의 시에 주어진 질의 시퀀스의 길이에 따라 생성되어 있는 인덱스 중에서 가장 적절한 것을 선택하여 탐색을 수행한다. 이때, 생성되어 있는 인덱스의 개수가 많을수록 탐색 성능이 향상된다. 필요에 따라 인덱스의 개수를 변화함으로써 탐색 성능과 저장 공간 간의 비율을 유연하게 조정할 수 있다. 질의 시퀀스의 길이 256 ~ 512중 다섯 개의 길이에 대해 인덱스를 생성하여 실험한 결과, 탐색 결과 선택률이 $10^{-2}$일 때 제안된 알고리즘의 탐색 성능이 순차 검색에 비하여 평균 2.40배, 선택률이 $10^{-5}$일 때 평균 14.6배 개선되었다. 제안된 알고리즘의 탐색 성능은 탐색 결과 선택률이 작아질수록 더욱 향상되므로, 실제 데이터베이스 응용에서의 효용성이 높다고 판단된다.

• The Journal of the Korea Contents Association
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• 제20권2호
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• pp.511-521
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• 2020

The purpose of this study is to research the effects of the same brand item sold online at different prices. To that end, the exploratory study is focused on four factors that influence price dispersion online is suggested. First, the products are divided into utilitarian products and hedonic products in line with the product concept, and laptops, washing machines are included in the utility concept products. Also the backpacks and sneakers are included in the hedonic concept products. A total of 400 effective objectives were selected and analyzed for each concept products, 200 objectives. The research analysis revealed that the price dispersion is significant relationship with an average price, the highest price, the lowest price, the year of release, the number of retailers, and the number of reviews in case of the utility concept product. On the contrary, in case of hedonic concept products, average price, highest price, lowest price, year of release, retailer, and reviews and ratings is found to be positively related to price dispersion. Based on these results, theoretical and practical implications are discussed about the influence price dispersion on marketing.

• Clinical and Experimental Pediatrics
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• 제52권4호
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• pp.494-498
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• 2009

Purpose : Applicability of transcatheter closure of atrial septal defect (ASD) has been expanded by accumulation of clinical experiences and evolutions of the device. This study was performed to evaluate the safety and efficacy of transcatheter closure of ASD with Amplatzer septal occluder (ASO) in young children less than 3 years of age. Methods : From May 2003 to December 2005, 295 patients underwent transcatheter closure of ASD with ASO in the Severance Cardiovascular Hospital, Yonsei University Health System. Among them, 51 patients less than 3 years of age were enrolled in this study. We investigated procedural success rate, rate of residual shunt, frequency of complications, procedure/fluoroscopy time, and need of modified techniques for device implantation. Results : The median age was 2.1 years and median body weight was 12 kg. Implantation of device was successful in 50 patients (98%). Seven patients (15%) showed a small residual shunt 1 day after the procedure, but complete occlusion had been documented at 6 month follow-up in all patients (100%). The pulmonary to systemic flow ratio (Qp/Qs), peak systolic pulmonary artery pressure, and peak systolic right ventricular pressure had decreased significantly after closure of ASD. There were 2 complications including device embolization (1, 2%) and temporary groin hematoma (1, 2%). Conclusion : Transcatheter closure of ASD with ASO can be performed with satisfactory results and acceptable risk even in young children less than 3 years of age. We could suggest that even in very young children with ASD, there is no need to wait until they grow to a sufficient size for the transcatheter closure.

• Clinical and Experimental Pediatrics
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• 제53권4호
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• pp.565-570
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• 2010

Purpose : To verify the efficacy and safety of lamotrigine (LTG) monotherapy in newly diagnosed children with epilepsy. Methods : We prospectively enrolled 148 children who had undergone LTG monotherapy at our institution between September 2002 and June 2009. Twenty-nine patients were excluded: 19 due to incomplete data and 10 were lost to follow up. The data of the remaining 119 patients was analyzed. Results : We enrolled 119 pediatric epilepsy patients (aged 2.8-19.3 years; 66 males and 53 females) in this study. Out of 119 patients, 29 (25.2%) had generalized epilepsy and 90 (74.8%) had partial epilepsy. The responses of seizure reduction were as follows: Seizure freedom (no seizure attack for at least 6 months) in 87/111 (78.4%, n=111) patients; partial response (reduced seizure frequency compared to baseline) in 13 (11.7%) patients; and persistent seizure in 11 (9.9%) patients. The seizure freedom rate was in 81.6% in patients with partial seizure (75.9% for complex partial seizure and 90.9% for benign rolandic epilepsy) and 44.8% in patients with generalized epilepsy (30.0% for absence seizure, 35.7% for juvenile myoclonic epilepsy patients, and 100.0% for idiopathic generalized epilepsy patients). Adverse reactions were reported in 17 (14.3%) patients, and 8 patients (6.7%) discontinued LTG because of rash and tic. No patient experienced severe adverse reaction such as Stevens-Johnson syndrome. Conclusion : LTG showed excellent therapeutic response and had few significant adverse effects. Our findings report may contribute in promoting the use of LTG monotherapy in epileptic children.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제26권9호
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• pp.1241-1248
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• 2002

Performance extension of the absorption refrigerator with LiBr solution is often faced to operate very close to the crystallization limit. Especially in the development of an air-cooled cycle, the crystallization of working solution in the system is a very difficult problem to overcome. This paper describes the cycle of hot water driven absorption system using a new working absorption solution instead of LiBr solution to improve the efficiency. In this study, we found out the characteristics of new working absorption solution through the cycle simulation and compared LiBr solution to evaluate. The effect of cooling water temperature, weak solution flow rate, hot water temperature and hot water flow rate were also examined. The COP is increased 22% higher in the case of LiBr＋Li1＋LiC1＋LiNO$_3$＋$H_2O$, 2% LiBr＋HO(CH$_2$)$_3$OH＋$H_2O$ than that of LiBr solution for the same operation condition.