• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.73-82
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• 2023

This study was conducted to investigate the effect of soil physico-chemical properties and crop growth responses for application of biochar derived from substrate with post harvest of oyster mushroom. The biochar was produced at 450~600℃ using a top-light up draft gasifier (TLUD) production system. As a result of elemental analysis, the biochar used was C 76.2%, H 2.5%, N 3.2%, and H/C was 0.39, which met the international certification standards for biocarbons (IBI) below 0.7. The chemical properties were 10.1 for pH, 1.0% for P₂O₅, 1.8% for K₂O, and 2.5% for CaO. The application rates of biochar were 0, 100, 200, 300, and 500 kg/10a. For cultivation of chinese cabbage and welsh onion, soil organic matter (OM), total nitrogen (T-N), total carbon (T-C), Ex.cation K contents and cation exchange capacity (CEC) in the treatments were increased compared to the no treatment. In addition, the bulk density was lowered and the porosity was increased, improving the soil physical properties in the treated soil. The growth of chinese cabbage and green onion increased with the application of biochar, but the yields of chinese cabbage and green onion did not significantly different among the treatments. Soil carbon sequestration in the treatments enhanced with increasing the amount of biochar application. It is expected to apply the biochar derived from spent oyster mushroom substrate in the eco-friendly farm soil management, improving soil physico-chemical properties.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.1
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• pp.3-11
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• 1995

This study was conducted to estimate the stabilization degree of compost which made from Korean food wastes. To make the compost, food wastes were mixed with dried paper sludge, sawdust and the rotten wood waste which had cultivated mushrooms, and then mixture was composted in $1.1m^3$ of chamber which installed with the blower for maintaining the aerobic condition. Y value, EC and pH were changed remarkably for the early stage of composting. These changes showed that the compost of food wastes could be stabilized within 30~35 days and that the substrate, food wastes, can be easily used as energy source for microorganisms. Although these phyico-chemical properties indicated that food wastes could be composted within 30 days during the composting, the temperature of pile maintained over $50^{\circ}C$ for 80 days, and C/N ratio decreased gradually for over 50 days. In conclusion, more than 50 days were required to stabilize the compost of food wastes.

• The Journal of Information Systems
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• v.30 no.4
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• pp.119-152
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• 2021

The concept of Self-Sovereign Identity (SSI) has emerged to overcome the limitations of traditional centralized personal identity management systems in our society. Therefore, in this study, 36 seminal researches out of 112 collected studies were investigated with a systematic literature review method to deliver a core common definition as well as the research trends on SSI in the socioeconomic, legal and technological fields. SSI studies in the legal field have mainly considered the conflicts with relevant laws such as General Data Protection Regulation (GDPR) and privacy protection laws. The study of SSI in the technology field have looked at the trends of the technical components to implement SSI and discussed the necessities of establishing standards to increase interoperability for SSI diffusion worldwide. This study ultimately derived the core definition of SSI from a various academic fields as "a trust-based personal identity management system that enables autonomous self-identification by a identity owner without a centralized system or 3rd party intervention". The results of this study contribute to the understanding of the essential SSI concept which were varied on different research fields and industries. The results also provide a foundation for discovering various SSI-based business models, applications as well as future research opportunities. Furthermore, this study suggested that SSI must be developed with interdisciplinary manner among the socioeconomic, legal, and technological fields to be practically applicable system to enable autonomous self-identification by a identity owner in our society.

• Phonetics and Speech Sciences
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• v.14 no.1
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• pp.37-47
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• 2022

The purpose of the this study is to observe the effects of healthy adults' age on temporal features of speech and identify which could differentiate older and young adults. We examined speech rates(i.e., overall speaking rate, articulation rate), occurrence of pause, and duration of pause per utterance by utilizing the National Institute of Korean Language's open corpus. We selected a total of 30 healthy adults (10 young, 10 middle-aged, and 10 older adults) in this study. There were significant differences among the groups in the overall speaking rate, articulation rate, total occurrence of pause, the occurrence of pause between syntactic words, total duration of pause, and duration of pause between syntactic words. The older and middle-aged adults showed slower speech rates and longer and more frequent pause than young adults. But there were no significant differences among the three groups in terms of pause within syntactic word. The overall speaking rate significantly differentiated older adults from young adults. These findings suggested that the effect of speakers' age was reflected in gradual changes in the temporal features of their speech.

• Journal of the Korean Institute of Educational Facilities
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• v.11 no.3
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• pp.5-15
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• 2004

This study aims to review the reality of local educational officials in technical post, to investigate their needs and awareness for newly changing social environment, and to inspire them with alternatives and strategies for reforming and restructuring their organization. It examines and analyses the strong points and weak points of the organization, the methods for improving the operation systems and organizational structures and the problems in the personnel management in officialdom, especially unfairness between the executive and the technical officials through a questionnaire and interview. This study ascertains that most of the technical officials consider expert knowledge and experience as their strong point and think the negative image against its group as their weak point for the organizational development. Specially this article indicates that they are not satisfied with the job conditions and want to shift to the official in executive post.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.364-366
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• 2012

본 논문은 다중 객체 추적 시스템에 관한 연구로서, Online boosting 을 기반으로 다중 객체 추적 기술이 개발되었다. 기존의 Boosting 기반의 추적 기술과는 다르게 객체들간의 구별을 좀더 명확하게 하기 위하여, 프레임과 프레임간의 객체들끼리의 연결 시 공간적인 제약조건과 시간적 제약 조건을 이용하여 Online Boosting 알고리즘을 설계하였다. 본 시스템에서는 멀리 떨어져있는 객체들간에는 연관성이 낮다는 점을 보다 강력하게 고려하였기에 추적하는 과정에서 물체들끼리의 연관 오류가 줄어들었고, 이는 몇 개의 범용데이터를 이용한 실험을 통해 증명하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.201-203
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• 2013

본 논문에서는 SIFT 와 particle 특징 궤적을 이용한 새로운 행동 인식 시스템을 제안한다. 먼저, 영상에서 중요한 지역적 특징 정보를 얻기 위하여 SIFT 특징 점들을 탐지하고, 탐지한 특징 점들을 SIFT descriptor matching 기법을 이용하여 그 궤적을 추출한다. 또한, SIFT 특징 궤적들의 수량이 적은점과 영상내의 조명변화, 부분적 가려짐 등의 변화로 인해 SIFT 특징 궤적이 종종 없어지는 단점을 보완하기 위하여, SIFT 특징 궤적 주위에 particle 점들을 탐지하고, dense optical flow 기법을 기반으로 그 특징 궤적을 추출한다. 그리고 SIFT 와 particle 궤적의 중요도를 조절하기 위해 가중치를 부여한다. 제안한 행동 인식 시스템의 효율성을 범용 데이터 셋을 이용한 실험을 통해 증명하였다.

• Korean Journal of Plant Resources
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• v.34 no.2
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• pp.144-155
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• 2021

This study was conducted to analyze community structure and species composition of Abies koreana forest. Field survey was carried out from June, 2019 to 2020, September. 121 plots (20×20 m) were set up, 5 herb layer plots (3×3 m) were constructed for each plot, and there, Diameter at Breast Height(DBH), height, environmental factor were measured. It was analyzed that water stress did not have a significant effect on the factors affecting the growth of A. koreana in Mt. Halla-san, and in the case of Mt. Deokyu-san, the more forest stands located at the ridge, the higher the tree density. It was found that the factors affecting the distribution of Abies koreana were not consistent according to the environment of study site.

• Korean Journal of Organic Agriculture
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• v.32 no.1
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• pp.75-90
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• 2024

Biochar is a solid substance with a high carbon content, as it is made out of biomass pyrolyzed under the condition of limited oxygen. This product has attracted attention as an environment-friendly soil amendment because it contributes to carbon neutrally and has improvement effects on the soil environment. This study conducted an experiment to evaluate soil physiochemical properties and microbial community changes in a melon greenhouse according to the applied amount of biochar to investigate the growth characteristics and yields of melons accordingly. In soil physical properties, an increase in the applied amount of biochar resulted in a decrease in bulk density and an increase in porosity of the soil, improving air permeability. In soil chemical properties, an increase in the applied amount of biochar led to a increasing of pH, organic matter and available phosphate content. In the growth characteristics of melons, there was a growing tendency of plant height, leaf length and leaf width according to the increasing application of biochar until 10,000 kg/ha. Moreover, melon yields also increased as the amount of biochar, 13~16% higher in 10,000 kg/ha biochar application than no treatment. Compared differences among microbial communities in the soil according to the application of biochar and found that plant beneficial bacteria dominated in biochar treatments. This study demonstrated the potential of biochar as an effective soil amendment in melon greenhouse by showing improvements in soil physicochemical properties and microbial communities.

• Korean Journal of Labor Studies
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• v.24 no.2
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• pp.247-291
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• 2018

This study investigates the employment structure and the social safety net experience of the subcontracting cleaning workers in Korea, who have been main targets of the labor outsourcing despite the necessity and permanence of their labour. This study specifically focuses on the fact that these subcontracting cleaning workers are mostly female and in their old age, and analyzes how the combination of their age, gender, and employment structure leads to the (mis)match with the Korean social security system. Case study with in-dept interview method has been conducted to the old-aged female subcontracting cleaning workers in Korea. The result of this study is as follows. It was the income insecurity that led them to (re)enter the labour market, and the cleaning work was the almost the only wage work they could do considering their age and gender. Cleaning workers are mostly employed in the subcontracting company, and thus their labour contracts depend on the business contract period between the original and subcontracting company. Consequently, their employment relationship is mostly insecure unless they are guaranteed employment succession through the collective agreement of trade union. Moreover, it has been discovered that the employment insecurity due to the indirect employment relationship led to the poor labour conditions, low wage, and the exclusion from the social safety net.