최근 도시정비사업에서 공사비 분쟁이 급증하고 있다. 이는 도면 확정전 면적 당 총액 계약을 하고 준공시점에 정산하는 방식을 진행하다보니, 초기계약단 계에서 세부내역서 부재로 정확한 공사비 확정이 안된 상태에서 향후 도면확 정으로 변경계약시에 조합과 시공사 간의 공사비 의견 차이가 큰 원인이다. 정 부는 이를 개선하고자 2019년 ｢도시 및 주거환경정비법｣에 공사비 검증 제도 를 신설하여 법적보호장치를 마련했지만 공사비 분쟁은 증가하고 있다. 본 논문은 현행 ｢도시정비법｣상 공사비 검증제도의 현황과 문제점을 분석하고 실질적인 개선방안을 제시하는 것을 목표로 한국부동산원 공사비 검증제도, 정비사업 표준계약서, 코디네이터 파견제도, 건설분쟁 조정위원회 등 현행 제 도의 내용과 문제점을 분석했다. 이를 바탕으로 한국부동산원 공사비 검증의 강제성 도입, 표준 공사계약서의 세부 내역서 포함, 코디네이터의 법적지위 보장, 건설분쟁 조정위원회의 조정 효력 강화 및 전문가 양성을 개선 방안으로 제안했으며 개산견적을 활용한 세부내역서 작성방법을 도입하고 이에 초기계약에 적용하도록 법적강제성을 부 여하면 공사비 분쟁을 획기적으로 줄일 수 있을 것이다.

연구는 내항여객선의 상가 주기를 조정함으로써 연료비를 포함한 운항비용의 절감 가능성을 분석하는 데 목적이 있다. 선박의 연료 효율에 영향을 미치는 요소 중 하나인 선체부착생물은 선박과 해수 간 마찰을 증가시켜 더 많은 연료 소모를 유발하는 것으로 알려 져있다. 선박안전법에 따라 감항성 유지 및 운항 안전을 위해 매년 정기검사 또는 제1종 중간검사를 받아야 하는 내항여객선은 일반적으 로 이러한 검사에 대비하여 연 1회의 상가 수리를 통해 선체부착생물을 제거한다. 이에 본 연구에서는 실제 운항 중인 3척의 내항여객선 을 대상으로 AIS 데이터, 항해일지 및 상가 수리 비용 등의 자료를 수집하고, 연간 표준운항비용을 산정하였다. 이를 바탕으로 MATLAB 기반의 시뮬레이션을 통해 각 선박의 상가 주기별 운항 비용 산출하여 비용 절감 효과를 분석하였다. 분석 결과, 선박별로 최대 비용 절 감 효과가 나타나는 시점이 상이하였으나, 연료비 절감과 추가 상가 비용 간의 균형점이 존재함을 확인하였다. 본 연구는 내항여객선의 선체 유지관리에 있어 상가 주기 조정이라는 운영 전략을 정량적으로 분석하였으며, 선사의 유지보수 계획 수립에 실질적인 근거를 제공 한다는 점에서 실무적 의의가 있다.

구스 아스팔트(Guss Asphalt) 혼합물은 다짐 없이 시공이 가능한 포장재료로, 1970년대부터 강바닥판 교량에 활용되어 왔다. 본 연구 는 박스 구스 아스팔트 혼합물 공용수명 예측 및 생애주기 비용을 비교분석하기 위해 폴리머 개질 구스, TLA 및 SMA 세 가지 혼합 물의 반사균열 시험, 동탄성계수 시험 및 소성변형시험을 수행하였다. 또한, TxACOL 프로그램을 사용하여 공용수명을 예측하였으며, 예측 결과를 기반으로 각 포장의 생애주기 비용을 분석하였다. 본 연구의 목적은 혼합물의 성능평가를 통해 폴리머 개질 구스 아스팔 트 혼합물의 공용수명을 예측하고 생애주기 비용을 분석하는 것이다. 성능평가 시험결과 폴리머 개질 구스 아스팔트 혼합물이 TLA 구스, SMA 아스팔트 혼합물보다 반사균열, 피로균열 및 소성변형 저항성이 높은 것으로 나타났다. 포장설계 수명 예측 및 생애주기 비용분석결과 폴리머 개질 구스를 사용한 포장설계의 공용성이 가장 우수하며 가장 경제적인 것으로 나타났다.

This study investigated the characteristics of personal PM2.5 exposure among 109 participants residing in Seoul over a two-month period, from February 2024 to April 2024. The participants were categorized into four sub-populations, and personal exposure to PM2.5 was assessed using portable monitors, GPS, and time-activity diaries. To understand the time-activity patterns, the daily occupancy rate for different microenvironments was calculated. Additionally, daily PM2.5 exposure contribution and integrated exposure were quantified. A time series analysis was conducted to identify differences in time-activity patterns and PM2.5 exposure among the sub-populations. ANOVA analysis indicated statistically significant differences in PM2.5 concentrations across populations and microenvironments (p<0.05). However, post-hoc analysis revealed specific microenvironments within certain sub-populations where PM2.5 concentration differences were not significant (p>0.05). All sub-populations spent more than 90% of their time indoors, and the results for exposure contribution and integrated exposure indicated that the home, which had the highest occupancy rate, was the most significant contributor to PM2.5 exposure. This study is expected to serve as foundational data for future indoor air quality management and the development of personalized strategies for reducing PM2.5 exposure.

This study pioneers a transformative approach of discarded orange peels (Citrus sinensis) into highly porous carbon, demonstrating its potential application in energy storage devices. The porous carbon structure offers a substantial surface area, making it conducive for effective ion adsorption and storage, thereby enhancing capacitance. The comprehensive characterization, including X-ray diffraction, Fourier transform infrared, Raman spectroscopy, field emission scanning electron microscopy, and XPS verifies the material’s suitability for energy storage applications by confirming its nature, functional groups, graphitic structure, porous morphology and surface elemental compositions. Moreover, the introduced plasma treatment not only improves the material’s intensity, bending vibrations, and morphology but also increases capacitance, as evidenced by galvanostatic charge–discharge tests. The air plasma-treated carbon exhibits a noteworthy capacitance of 1916F/g at 0.05A/g in 2 M KOH electrolyte. long term cyclic stability has been conducted up to 10,000 cycles, the calculated capacitance retention and columbic efficiency is 92.7% and 97.6%. These advancements underscore the potential of utilizing activated carbon from agricultural waste in capacitors and supercapatteries, offering a sustainable solution for energy storage with enhanced performance characteristics.

As part of the KOPIA Paraguay Center rice pilot villages project, conducted from July 1, 2021, to the end of June 2024, this study examined the average yield and value of paddy rice harvested between January and April 2023 in five local rice pilot villages in Paraguay: Santa Rosa, Eusebio Ayala, Coronel Bogado, Santa Maria, and Yaguaron. The CEA-5K-PUNTA variety was planted in late August 2022 and subsequently harvested from January to April 2023. The farmers in the pilot villages received information on common pests, diseases, and weeds, including instructions on timing and the number of applications required for their control. They also received technical guidance on water management and weeding methods. The study found that the average yield per hectare in the pilot villages for the CEA-5K PUNTA variety in the 2022/2023 growing season was 794.50 kg/10a, compared to 477.17 kg/10a for the conventional variety IRGA 424 in the 2019/2020 season, which preceded the project. This indicates a 66.5% increase in yield per hectare for the pilot village farmers compared to the pre-project period (2020/2021). The analysis of paddy rice production value in the pilot villages, using the Difference in Differences method, revealed a 65.1% increase. Moreover, a financial analysis was conducted based on the addition of agricultural inputs to the paddy fields during the period from the end of August 2022 to January-April 2023. The analysis showed that the total cost was US$597.25 per hectare, while the gross income was US$1,685.3 per hectare. As a result, the net profit per hectare amounted to US$1,088.05.

Given the recent increases in feed cost, the demand for rice straw has been increasing on dairy farms because it is cheaper than expensive imported forages. Therefore, it is necessary to study the effect of rice straw feeding on the growth and productivity of dairy heifers. This study compared how feeding tall fescue and rice straw affects the growth, age at first calving, and feed cost of heifers. we compared the growth, age at first calving, and feed cost for each group during the breeding period. Body height was higher in the tall fescue-fed group than in the rice straw-fed group (p<0.05). The length of the growing stage was significantly shorter in the tall fescue group than in the rice straw group (p<0.001) and the age at calving also showed a significant reduction in the tall fescue group compared to the rice straw group (p<0.001). However, the feed cost was lower in the rice straw group because of the difference in the unit price of forage (p<0.001). Based on these results, during the growing period, the rice straw group had delays in growth and the age at first calving compared to the tall fescue group, but also had reduced feed costs in the short term.

In this research, reduced graphene oxide/polypyrrole (rGO/PPy) particles were synthesized and used to measure the amount of dopamine (DA) electrochemically. The obtained rGO/PPy particle was characterized by Fourier Transform Infrared Spectrophotometer (FTIR), UV–Visible Spectrophotometer (UV–Vis), and X-Ray Diffraction Diffractometry (XRD). To investigate the DA sensor performance, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to acquire electrochemical measurements of the sensor. Current values of 1.65 and 5.9 mA were observed in the CV at 0.2 mM and 1.2 mM concentrations of target molecule, respectively. Under optimized conditions, the linear calibration plots were found to exhibit significant sensitivity in the linear range of 0.2 and 1.2 mM, with a corresponding detection limit of 0.061 μM for DA. The results obtained were similar to the sensor results of DA made using precious metals. This work was a demonstration of the feasibility of high-sensitivity electrochemical analysis with conductive carbon materials without the use of precious metals. It was also observed that the cost-effective rGO/PPy exhibited a very high potential for DA detection.

The Korean military has sought to build an all-round military force against the national and international security environment and future asymmetric threats as well as the military threats it faces. However, while raising the need for timely electrification, there are few cases of quantitatively evaluating the loss when electrification is delayed, making it difficult for our military to provide a logical basis to support the importance of the electrification period. Therefore, through this study, we tried to analyze the index of loss cost that can support the need for timely electrification with logical and quantitative data and present it as a logical basis. To this end, the loss cost was calculated in terms of combat efficiency, equipment utilization rate, and maintenance requirements, which can be quantitatively calculated based on “combat readiness,” a general impact on the military in case of delayed timely electrification.

해양경찰공무원은 직무를 수행하면서 조직의 목표 뿐만 아니라 개인의 삶과 연결되어 있다. 이에 해양경찰공무원의 직업 소명 의식과 직무열의는 중요한 요소이다. 따라서 이 연구는 해양경찰공무원의 발전에 대한 직업소명의식과 직무열의의 관계를 검증하는데 주 목적이 있다. 연구의 진행을 위해 해양경찰공무원 136명을 대상으로 연구를 진행하였다. 직업소명의식의 하위변인은 초월적 부름, 목적· 의미 존재, 친사회적 지향 동기로 구성되었으며, 직무열의는 활력, 몰두, 헌신으로 구성하였다. 검증 결과 해양경찰공무원이 인식하는 직 업소명의식 하위변인인 초월적 부름과 목적·의미 존재는 직무열의의 하위변인 활력, 헌신, 몰두에 정(+)의 영향을 미치는 것으로 나타났 다. 그러나 직업소명의식 하위변인 친사회적 지향 동기는 직무열의 하위변인인 활력, 헌신, 몰두에는 영향을 미치지 않는 것으로 나타났 다. 분석 결과를 통해 해양경찰 조직의 실무적 시사점을 제안하였다.

In this study, we analyzed how the revenue water ratio(RWR) is affected by changes in conditions of the water supply area, such as the ratio of aging pipes, maintenance conditions, and revenue water. As a result of analyzing the impact of pipe aging and maintenance conditions on the RWR, it was confirmed that the RWR could be decreased if the pipe replacement project to improve the aging pipe ratio was not carried out and proper maintenance costs were not secured. It was also confirmed that an increase in the revenue water could be operated to facilitate the achievement of the project’s target RWR. In contrast, a decrease in the revenue water due to a population reduction could affect the failure of the target RWR. In addition to analyzing the causes of variation in the RWR, the calculation of estimated project costs was considered by using leakage reduction instead of RWR from recent RWR improvement project cost data. From this analysis, it was reviewed whether the project costs planned to achieve the target RWR of the RWR improvement project in A city were appropriate. In conclusion, the RWR could be affected by variations in the ratio of aging pipes, maintenance conditions, and revenue water, and it was reasonable to consider not only the construction input but also the input related to RWR improvement, such as leakage reduction, when calculating the project cost.

PURPOSES : This study is aimed to economic analysis of the ferronickel slag pavement method carried out to suggest the necessity of developing ferronickel slag pavement technology. METHODS : A life cycle cost analysis of the application of the Ferronickel Slag pavement method and the cutting + overlay pavement method was performed to compare the economic indicators and greenhouse gas emissions for each pavement method. RESULTS : As a result of the analysis, regardless of the Ferronickel Slag mixing rate, if the common performance of the Ferronickel Slag pavement method is the same or superior to the existing pavement method, it is more economical than the existing pavement method. Furthermore, the lower the maintenance cost of the Ferronickel Slag pavement method, the higher the economic feasibility due to the high Ferronickel Slag mixing rate. Greenhouse gas emissions can be reduced from at least 9% to up to 53% through the application of the Ferronickel Slag pavement method, except for some scenario analysis results. CONCLUSIONS : This study provided that the Ferronickel Slag pavement method was superior to the existing pavement method in terms of economic and environmental aspects. Therefore, it was found that the objective justification of developing road pavement technology using Ferronickel Slag was secured.

PURPOSES : Construction cost estimates are important information for business feasibility analysis in the planning stage of road construction projects. The quality of current construction cost estimates are highly dependent on the expert's personal experience and skills to estimate the arithmetic average construction cost based on past cases, which makes construction cost estimates subjective and unreliable. An objective approach in construction cost estimation shall be developed with the use of machine learning. In this study, past cases of road projects were analyzed and a machine learning model was developed to produce a more accurate and time-efficient construction cost estimate in teh planning stage. METHODS : After conducting case analysis of 100 road construction, a database was constructed including the road construction's details, drawings, and completion reports. To improve the construction cost estimation, Mallow's Cp. BIC, Adjusted R methodology was applied to find the optimal variables. Consequently, a plannigs-stage road construction cost estimation model was developed by applying multiple regression analysis, regression tree, case-based inference model, and artificial neural network (ANN, DNN). RESULTS : The construction cost estimation model showed excellent prediction performance despite an insufficient amount of learning data. Ten cases were randomly selected from the data base and each developed machine learning model was applied to the selected cases to calculate for the error rate, which should be less than 30% to be considered as acceptable according to American Estimating Association. As a result of the analysis, the error rates of all developed machine learning models were found to be acceptable with values rangine from 17.3% to 26.0%. Among the developed models, the ANN model yielded the least error rate. CONCLUSIONS : The results of this study can help raise awareness of the importance of building a systematic database in the construction industry, which is disadvantageous in machine learning and artificial intelligence development. In addition, it is believed that it can provide basic data for research to determine the feasibility of construction projects that require a large budget, such as road projects.

청중비용이론은 국제관계학에서 가장 첨예한 논쟁의 대상이 되어 왔 다. 이 이론에서 도출된 여러 가설은 연구 방법에 따라 확증이 되기도 하고 때로는 반증이 되기도 했다. 그 결과, 청중비용이론의 경험적 유용 성에 대한 찬반 논쟁이 현재까지 지속되고 있다. 본 연구는 이러한 논쟁 을 일정부분 해소하기 위해 청중비용이론의 경쟁 가설 모두에 가장 부합 해야 하는 사례(most likely case)를 선택하여 과정추적(process tracing) 검증을 시도한다. 이를 위해 우리는 양적 연구자의 가설이 지지(반증)되 면 질적 연구자의 가설이 반증(지지)되는 방식으로 연구를 설계했다. 검 증 대상 가설은 ‘약속이행의 의지’와 관련된 두 가지 경쟁 가설과 ‘국내 정치적 처벌’과 관련된 두 가지 경쟁 가설이다. 검증을 위해 선택된 사례 는 제2차 북일 정상회담이다. 분석 결과는 혼재되어 있다. 약속이행의 의지와 관련해서는 양적 연구자의 가설이 지지되고, 국내정치적 처벌과 관련해서는 질적 연구자의 가설이 지지된다. 이 두 가지 가설을 종합할 경우, 최선을 다하는 지도자의 모습을 인지한 청중은 절반의 성공 또는 절반의 실패에 대해서 관대하다는 결론이 도출된다. 이러한 발견은 민주 국가 지도자에게 희소식일 수 있다.

Benzene, toluene, ethylbenzene, and xylenes are commonly known as (BTEX) and include volatile organic compounds (VOCs) in ambient air. Exposure to some BTEX has been associated with health risks. This study aimed to reduce BTEX on the environment and human health dramatically. This research targeted decreasing the BTEX in an air environment by producing high surface area activated carbon (KA-AC) under optimized synthesis conditions from Ricinus communis as lignocellulosic waste using ZnCl2 solution, respectively. The influence of several activation parameters was investigated on the surface area, such as impregnation ratio, carbonization time, and carbonization temperature. The KA5-AC prepared under optimized conditions showed BET surface area and total pore volume of 1225 m2/ g, and 0.72 cm3/ g, respectively. The optimized synthesis conditions were as follows: 0.1, 0.5, 1, 2, and 5 M impregnation ratio, 450–950 °C carbonization temperature, and 100 min carbonization time. The characteristics of the optimized KA-AC were analyzed using nitrogen adsorption–desorption isotherm, scanning electron microscopy, and pore structural analysis. The results confirmed that the VOCs adsorption on KA-AC followed a monolayer adsorption isotherm over a homogeneous adsorbent surface. It showed the removal efficiency of benzene, toluene, ethylbenzene, and m, p-xylene (R2 = from 0.991 to 0.997). Moreover, the KA-AC exhibited good performance without considerable loss of efficacy throughout the experiments. Accordingly, it is concluded that developing low-cost activated carbon to use BTEX vapor adsorption research could be practical and developments to overcome for utilization in air pollution control.