This study investigated the seasonal water quality characteristics of two key environmental flow sources for the Gwangju Stream: the Yeongsan River water supply and effluent from a sewage treatment plant. Monitoring data collected between 2019 and 2023 were analyzed for both sources, and field surveys from October 2023 to June 2024 examined confluence points where environmental flows entered the Gwangju Stream, measuring both main-stream and inflow waters. The Yeongsan River supply recorded its highest spring organic matter levels (mean BOD: 5.2 mg L-1; maximum: 8.7 mg L-1), while the sewage treatment plant effluent exhibited pronounced seasonal variation in total nitrogen (T-N), ranging from a summer low of 8.2 mg L-1 to a winter high of 13.8 mg L-1. Upstream water quality remained stable; however, downstream BOD increased annually by 8.2%, and total phosphorus (T-P) peaked sharply in summer (0.567 mg L-1). Field survey results indicated that in spring, T-N increased by up to 495%, BOD by 182%, and T-P by 290%; in winter, T-N rose by 239%, BOD by 164%, and COD by 73%. These findings reveal marked seasonal variability in the influence of environmental flow sources, with T-N showing the most substantial increase in spring. The results highlight the need for targeted nutrient management strategies, such as increasing the proportion of the plant’s effluent in spring to stabilize nutrient loads and improving its biological treatment efficiency in winter to reduce T-N concentrations. Season-specific measures of this kind can improve water quality and help sustain the ecological integrity of the Gwangju Stream.

This study analyzed the emission characteristics of major air pollutants from 97 domestic municipal solid waste incineration facilities using tele-monitoring system (TMS) data collected from 2015 to 2023. Focusing on the effects of the enforcement of enhanced national emission standards in 2019, this research examined changes in emission factors (EFs) of dust and nitrogen oxides (NOX) by facility capacity and aging level. The results showed that the average EFs for dust and NOX significantly decreased by up to 30% after enforcement (p<0.01~0.001), indicating the practical effectiveness of the strengthened standard. This trend was observed consistently across all facility sizes and aging levels, including large-scale and older facilities. In contrast, hydrogen chloride (HCl) and carbon monoxide (CO) did not show clear reductions and remained highly variable, suggesting that emission standards alone may not be sufficient for stable control. These findings demonstrate the need for optimized combustion conditions and improved post-treatment systems for pollutants such as HCl and CO. This study provides empirical evidence highlighting the importance of appropriate facility scale and systematic refurbishment cycles for stable emission reduction in municipal waste incinerators.

This study analyzed fall accidents involving boatswain’s chairs over the past ten years to investigate their underlying causes and effective preventive measures. The fall accidents in this study were classified according to construction type, work category, and sequence of work. Next, their direct causes were identified by applying the concept of serious injury factor. A focus group interview was conducted with six experts in boatswain’s chair-type scaffolding to derive preventive measures. The results of the investigation indicate that the majority of accidents occurred in maintenance works among construction types, and painting, caulking, and cleaning tasks among work categories. In terms of work sequence, most fall accents occurred while working with descending due to rope defects (loosening, breakage, or insufficient length) and anchorage failures. Based on these findings, two key preventive measures were proposed: (1) installing lifelines as a fail-safe measure to provide safety redundancy, and (2) implementing inherent safety measures to prevent rope defects and failures such as regular inspections, use of high-performance ropes, and ensuring proper anchorage strength. The findings of this study can be utilized in development of effective safety guidelines and policies for boatswain’s chair operations.

This study investigates the vibration characteristics of an aluminum subframe for small and high-speed vessels through modal and resonance analysis using the finite element method (FEM). Due to the low stiffness and damping of aluminum, concerns arise over structural resonance and fatigue. A 3D model based on actual design drawings was analyzed to extract six natural frequencies and corresponding mode shapes. Significant deformation was observed in the first and second modes (90.65 Hz, 110.60 Hz), which may overlap with operational frequencies. The fifth mode (263.70 Hz) showed high amplitude with Y-axis concentration, indicating lateral resonance vulnerability. Deformation ratios were used to identify dominant vibrational directions. Based on the findings, design strategies such as structural reinforcement, RPM adjustment, and damping device application were proposed to improve vibration safety in the early design stage.

본 연구에서는 벼메뚜기 탈지 추출물을 이용한 친환경 적인 은나노입자(AgNPs)의 생합성 가능성을 확인하고, 합 성된 AgNPs의 물리·화학적 특성과 항균 활성을 평가하였 다. AgNPs의 형성은 용액 색상 변화와 함께, 448 nm 부 근에서 특유의 표면 플라스몬 공명 흡광 피크가 관찰된 UV-Vis 스펙트럼을 통해 확인되었다. DLS 및 zeta potential 분석 결과, 평균 입자 크기는 98.4±0.9 nm, zeta potential은 -22.8±0.5 mV로 안정적인 분산 특성을 나타냈다. TEM 및 HR-XRD 분석을 통해 구형의 결정성 입자가 관찰되었 고, FT-IR 결과에서는 단백질 유래 작용기가 AgNPs의 환 원 및 안정화에 관여한 것으로 나타났다. 항균 활성은 disk diffusion assay를 통해 확인되었으며, 합성된 AgNPs는 S. Typhimurium, E. coli, S. aureus, B. cereus를 포함한 4종 식중독균에 대해 유의미한 항균 효과를 보였다. 이상의 결 과는 벼메뚜기 탈지 추출물이 AgNPs의 생합성 소재로 활 용 가능함을 시사하며, 향후 식품안전 응용에 활용될 수 있는 가능성을 제시한다.

This study examined the operational characteristics and fishing performance of an offshore pot fishery targeting swimming crabs (Portunus trituberculatus) to identify key issues and proposed strategies for improving efficiency and fisher safety. Analysis was based on approximately one year of fishing logbook data recorded by a pot fishing vessel. The total annual catch amounted to 30,084 kg, with the highest catch per unit effort of 0.07 kg per trap observed in autumn at depths of 20–25 m. No crabs were caught below 15℃ while the peak catch occurred at around 25℃. Catches were geographically concentrated in the mid-northern West Sea, especially near Taean and Boryeong. Economically important bycatch species, including sand crabs, octopus, and turban snails, exhibited distinct spatial distributions. An average of 1,996 traps were deployed per operation with a low loss rate of 1.6 traps. Based on field-level observations, this study proposed the development of automated or semi-automated equipment, such as bait cutters, automatic mainline arranging devices, pot-hauling and separation systems, chilled water tanks for sorting, and automated unloading systems. These technologies are expected to reduce labor demands, improve safety, and enhance the overall operational efficiency of the pot fishery.

Parking lots are environments in which various types of vehicles such as passenger cars, trucks, and personal mobility (PM) devices coexist. Despite numerous studies analyzing parking lot crash characteristics, PM devices have received limited attention. Analyzing parking lot crash characteristics involving PMs is essential, given that the market penetration rate of PM is increasing. This study quantitatively analyzed the severity characteristics of vehicle-to-PM crashes in parking lots by aggregating the number of crashes and identified factors influencing crash severity through the development of an ordered probit model. According to the quantitative analysis results, PM users experienced a higher crash severity owing to insufficient personal protective equipment. Additionally, crashes involving parked or illegally parked PMs tended to have a lower severity than those involving PMs being ridden. The developed crash severity model identified several key factors, including crashes related to illegally parked vehicles, crashes in which a vehicle was at fault for a collision with a parked PM, cases in which the vehicle type of the at-fault driver was a passenger car, and cases in which the at-fault driver was a female. A higher probability of property damage crashes, rather than injury or fatal crashes, was observed in cases involving parked or illegally parked PMs owing to lower relative speeds. Passenger cars generally have shorter braking distances than trucks or buses, allowing quicker responses to sudden situations. A female at-fault driver may experience longer perception–reaction times, potentially increasing the probability of injury or fatal crashes. The findings of this study can provide foundational data for revising ordinances or laws to enhance parking lot safety or preliminary data for developing parking lot management systems. Furthermore, the identified crash severity factors can be prioritized to develop effective measures for crash prevention and severity reduction in parking lots.

This study identified the effects of factors related to physical fashion brands’ sales promotions on consumers’ reactions and purchase intentions, while also determining the differences in these effects according to the consumers’ generations and genders. For the empirical analysis, the study used SPSS and AMOS 25.0, with frequency analysis, EFA, reliability analysis, CFA, SEM analysis, and multiple-group comparison analyses also performed. The results of multiple-group comparison analyses of the generation groups showed that the effects of consumers’ affective reactions on their purchase intentions differed between the MZ generation(a generational group comprising the millennial generation and Gen Z) and active seniors, with the influence on the active seniors group greater than on the MZ generation group. The effects of cognitive reaction on purchase intention also differed between the two groups, with the influences on the active seniors group again greater than on the MZ generation, moreover the result was significant only for the active seniors group. The influence of affective reactions on purchase intention also differed in the result of the comparison of gender groups, with the impact greater for male consumers than for female consumers. Finally, the effect of cognitive reactions on purchase intention was greater for female consumers than male consumers, with the result significant only for female consumers. Based on these findings, the study recommends adopting different sales promotion strategies for each consumer group to induce positive purchasing behavior.

A high-pressure in-situ permeation measuring system was developed to evaluate the hydrogen permeation properties of polymer sealing materials in hydrogen environments up to 100 MPa. This system employs the manometric method, utilizing a compact and portable manometer to measure the permeated hydrogen over time, following high-pressure hydrogen injection. By utilizing a self-developed permeation-diffusion analysis program, this system enables precise evaluation of permeation properties, including permeability, diffusivity and solubility. To apply the developed system to high-pressure hydrogen permeation tests, the hydrogen permeation properties of ethylene propylene diene monomer (EPDM) materials containing silica fillers, specifically designed for gas seal in high-pressure hydrogen environments, were evaluated. The permeation measurements were conducted under pressure conditions ranging from 5 MPa to 90 MPa. The results showed that as pressure increased, hydrogen permeability and diffusivity decreased, while solubility remained constant regardless of pressure. Finally, the reliability of this system was confirmed through uncertainty analysis of the permeation measurements, with all results falling within an uncertainty of 11.2 %.

그늘은 일사를 차단하여 여름철 도시 열환경을 완화한다. 본 연구는 가로 공간에서 수목 식재를 통해 그늘을 효과적으 로 확대할 수 있는 수목 특성(수고·지하고)을 규명하기 위해, 특성별 그늘 분석 시나리오를 구축하고 그늘 면적 변화를 분석하였다. ArcGIS Pro의 Sun Shadow Frequency 도구를 활용해 그늘 길이가 가장 짧은 하지(6월 21일)를 기준일로 설정하고, 수고 시나리오(8 m·15 m·20 m)와 지하고 시나리오(1.5 m·3 m·4.5 m)를 구성하였다. 분석 결과, 수목은 보행로의 그늘 면적을 크게 확대했으며, 수고가 높고 지하고가 낮을수록 그늘 면적이 증가하였다. 동–서 방향 북측 가로가 수목 그늘의 영향을 가장 많이 받았고, 남측 가로는 거의 영향을 받지 않았다. 남–북 방향 가로에서는 태양 위치에 따라 양측 가로의 그늘 면적이 대칭적으로 변했으며, 건물 그늘과 수목 그늘이 상호 보완적이었다. 본 연구는 시간대·가로 방향·수목 특성에 따라 보행로 그늘의 양과 공간 분포가 달라진다는 점을 실증적으로 제시하였다. 이 결과는 정부·지자체의 그늘 확대 정책, 가로수 조성 지침, 도시 녹지 계획 수립을 위한 기초자료로 활용될 수 있다.

This study analyzed the emission characteristics of major air pollutants (dust, nitrogen oxides, hydrogen chloride, and carbon monoxide) emitted from domestic public waste incineration facilities based on their operating elements. Using automatic measuring equipment for smokestacks (TMS), data was collected from 97 facilities from 2015 to 2023. The emission source unit (kg/ton) was evaluated based on the facility’s capacity, aging level, and incineration type. Emissions were calculated, and descriptive statistical analysis was performed based on the mean, standard deviation, and coefficient of variation. As a result of the analysis, it was found that the larger the facility capacity, the lower the average emission and volatility, which suggests that the operational stability of large facilities is high. On the other hand, facilities that had deteriorated for 10 to 15 years had the highest emission rates, and emissions decreased in facilities that were aged more than 20 years. In addition, the pyrolysis and high-temperature melting incineration facilities had lower NOx and HCl emissions than the conventional incineration type. Furthermore, CO showed the greatest volatility overall, which was found to be particularly difficult to manage in facilities in the early to mid stages of aging. These results provide empirical evidence that the structural characteristics and incineration type of incineration facilities have a significant impact on air pollutant emissions and can serve as useful basic data for policy-making, including for implementing region-wide initiatives and planning major repairs in the future.

본 연구에서는 교목성 낙엽침엽수인 메타세쿼이아(Metasequoia glyptostroboides)가 가로수로 식재된 국내 8개 지역(삼척, 대전, 대구, 구미, 포항, 부산, 진안, 담양)의 10개 도로에서 총 280본을 대상으로 결함 및 관리 특성을 조사하였다. 육안 평가를 기반으로 2022년과 2023년 6~7월에 기본 현황, 결함, 관리 특성을 종합적으로 분석하였다. 결함도는 고사지, 줄기 상처, 병해충 등을 조사하여 정량화하였다. 메타세쿼이아의 평균 수고는 17.8m, 흉고직경 43.2cm, 근원직경 62.3cm, 수관폭 7.7m, 지하고 4.1m였으며, 흉고직경과 수고 간에는 전반적으로 양의 상관관계가 확인되었다. 그러나 흉고직경 기준 수고 예측 모델을 사용하였을 때 자연 집단보다 수고가 최대 11.9m 낮았다. 결함도는 평균 2.21점으로, 근계 결함(96.79%), 해충 피해(60.00%), 고사지(46.79%)가 가장 빈번했다. 보호틀 폭은 대부분 1~2m였으나 일부 구간은 1m 내외로 근계 손상이 발생하였고, 전선 비지중화 구간에서는 가지치기로 인해 수형이 고착되는 경향을 보였다. 교목성 가로수로서 전국적으로 조성된 메타세쿼이아 가로수의 지속 가능한 관리를 위한 종합적인 방안을 강구하는 것이 필요하다.

본 연구는 응답자의 특성에 따른 정원 조성 및 관리 의향, 선호하는 정원 유형 차이를 확인하고, 정원 조성 의향 증진 전략을 제시하여 정원 설계에 유용한 기초자료를 제공하는데 목적을 두고 있다. 이에 본 연구에서는 2024년 8월 12일부터 9월 13일까지 설문조사를 실시하였고, 회수된 설문 중 부절절한 설문지를 제외한 183부의 설문을 분석하였다. 그 결과 인구통계학적 특성 중 응답자의 특성으로 직업적 배경의 경우 관련 업계 종사자가 72명(39.3%)으로 가장 많았고, 일반시민 59명(32.2%), 전공학생이 52명(28.4%) 순으로 나타났다. 응답자 특성에 따른 정원 조성 의향 및 관리 차이에서 관련 업계 종사자와 전공 학생들이 일반 시민에 비해 정원 조성에 관심이 더욱 많았으며, 정원 관리에 사용하는 시간도 더욱 많은 시간 소요하고 싶다는 것으로 나타났다. 선호하는 정원 유형으로는 “나무를 위주로 한 정원(64.0%)”, “이색적인 정원(60.6%”), “꽃과 채소, 과수 등이 같이 있는 정원(59.9%)” 순으로 긍정적 선호 비중이 높았으며, 부정적 선호가 많은 정원으로는 “단일 화종 위주의 정원(23.9%)”이었다. 정원 조성 의향에 미치는 선호하는 정원 선호 유형으로는 “한국식 정원”, “서양식 정원”, “토피어리 정원”, “수경 정원”, “나무를 위주로 한 정원”, “꽃과 채소, 과수 등이 같이 있는 정원”이 통계적으로 유의미한 양적 상관을 가지고 있는 것으로 나타났다. 또한, IPA 분석을 통한 정원 조성 의향 증진 전략을 위한 정원 유형으로는 “서양식 정원”에 적극적 자원 투자로 중점 개선해야하는 것으로 확인되었다.

As digital transformation accelerates, platform business has become a core business model in modern society. Platform business has a network effect where the winner takes all. For this reason, it is crucial for a company's pricing policy to attract as many customers as possible in the early stages of business. Telecommunication service companies are experiencing stagnant growth due to the saturation of the smartphone market and intensifying competition in rates, but the burden of maintaining communication networks is increasing due to the rapid increase in traffic caused by domestic and foreign CSPs. This study aims to understand the dynamic characteristics of the telecommunications market by focusing on pricing policy. To this end, we analyzed how ISPs, CSPs, and consumers react to changes in pricing policy based on the prisoner's dilemma theory. The analysis of the dynamic characteristics of the market was conducted through simulation using the Agent-Based Model.

이 연구는 시설 내 노인학대의 지속적 증가와 구조적 요인에 주목하여, 시설 환경에 서 발생하는 노인학대의 구조적 특성과 교정적 개입 방안을 다각도로 분석하였다. 민･ 형사･행정 판례와 최근 국내외 선행연구를 종합 분석한 결과, 시설 내 노인학대는 인 력 부족, 낮은 근로환경, 조직문화의 결함, 감독 시스템 부재 등 복합적 구조적 요인이 작용함이 확인되었다. 특히 방임, 신체적･정서적･경제적 학대, 성적 학대 등이 반복 적･조직적으로 발생하고 있으며, 신고･처벌 위주의 기존 대응은 실질적 예방과 재발 방지에 한계가 있는 것으로 나타났다. 이에 본 연구는 구조적 개선과 함께, 가해자 대 상 교정적 프로그램 개발, 조직문화 혁신, 직원 교육 강화 등 다양한 정책적･실천적 제언을 제시하였다. 본 연구는 실효성 있는 예방 및 재발 방지 대책 마련에 기초 자료 로 활용될 수 있을 것이다.

기후변화로 인해 전 세계적으로 수온이 상승하는 추세이며, 그에 따른 수계 내 유기물의 농도 증가에 따라 정수 처리 과정에서의 소독부산물 생성량 역시 상승하고 있다. 이 중 총트리할로메탄(Trihalomethanes, THMs)은 발암물질로 분류되며, 먹는 물 수질 기준이 0.1 mg/L로 설정되어 있다. 소독부산물 생성량 증가와 취수원에서의 수질 문제가 지속적으로 제기됨에 따라 안정적 수돗물 공급을 위한 대책이 필요한 상황에서 본 연구는 여름철 경기도와 경상북도 지역의 수도꼭지에서 THMs 농도를 모니터링 하였다. 또한, 과거 THMs 측정 자료와 더불어 다양한 자료를 비교ㆍ분석하여 THMs 농도 변화의 원인을 파악했다. 그 결과, 조사 지역들의 THMs 생성에는 원수의 종류, 그로 인한 용존유기탄소 (Dissolved organic carbon, DOC), 클로로필-a 인자와 더불어 계절적 요인들 중 기온과 강우량이 종합적으로 기여하는 것으로 나타났다. 특히, 선형 회귀분석을 통해 용존유기탄소와 THMs간의 상관관계가 높으며 수돗물의 용존유기탄소 농도가 2.7 mg/L 이상일 경우 THMs 농도가 법정 먹는 물 수질 기준을 초과할 가능성이 높다는 결과를 도출하였다. 이를 통해 여름철 강우가 집중되는 시기와 갈수기 THMs 관리를 위해 원수의 유기물 농도를 관리하는 노력이 필수적임을 확인하였다. 해당 결과는 정수장에서의 유기물 농도 관리를 통해 THMs 생성을 억제하는 것이 매우 중요함을 시사하며, 앞으로 먹는 물 수질 기준과 정수장 운영 관리에 용존유기탄소 수질 항목을 추가하는 방안의 검토가 필요하다 판단된다.