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.

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.

In supply chain, most partners except the top level suppliers have inbound and outbound logistics. For example, toll manufacturing companies get unprocessed materials from a requesting company and send the processed materials back to the company after toll processing. Accordingly, those companies have inbound and outbound transportation costs in their total logistics costs. For many cases, the company may make the schedule of distributions by considering only the due delivery dates. However, the inbound and outbound transportation costs could significantly affect the total logistics costs. Thus, this paper considers the inbound and outbound transportation costs to find the optimal distribution plans. In addition, we have considered the inventory holding costs as well with transportation costs. From the experimental results, we have provided the optimal strategies for the distributions of replenishment as well as deliveries.

In this paper, an alternative inventory policy that trades off the bullwhip effect at an upstream facility with cost minimization at a current facility, with the goal of reducing system wide total expected inventory costs, when external demand distributjon is autocorrelated, is considered. The alternative inventory policy has a form that is somewhere between one that completely neglects the autocorrleation and one that actively utilizes the autocorrelation. For this purpose, a mathematical model that allows us to evaluate system wide total expected inventory costs for a periodic review system is developed. This model enables us to identify an optimal inventory policy at a current facility that minimizes system wide total expected inventory costs by the best tradeoff of the bullwhip effect at an upstream facility with cost minimization at a current facility. From numerical experiments, it has been found that (i) when the autocorrelation is negative, the optimal policy is one that actively utilizes the autocorrelation, (ii) when the autocorrelation is small and positive, the optimal policy is one that neglects the autocorrelation, and (iii) when the autocorrelation is large and positive, the optimal policy is somewhere between one that actively utilizes the autocorrelation and one that neglect the autocorrelation.

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.

This study attempted to analyze the comparative advantage in terms of disaster safety costs in verifying the effectiveness and economic feasibility of the high-performance water-bulwark system in the pole tunnel, which was recently promoted as a part of the acceleration of vehicles. The tunnel to be analyzed was divided into a short tunnel(Anyang, Cheonggye) and a long tunnel(Suraksan, Sapaesan). As a result, it was analyzed that 25% of the improvement effect would occur if one lane was secured by applying the Water-Bulwark System. It was analyzed that this is because the time value cost, which accounts for a large proportion of the traffic congestion cost of short tunnels and pole tunnels, differs depending on the congestion time and traffic volume, not the length of the tunnel.

This study aims to analyze the cost of climate change damages to laver and sea mustard aquaculture, which are considered to be highly vulnerable to climate change in Korea. For this purpose, the correlation between aquaculture production and climate factors such as water temperature, salinity, air temperature, and precipitation was estimated using a panel regression model. The SSP scenario was applied to predict the changes in production and damage costs due to changes in future climate factors. As a result of the analysis, laver production is predicted to decrease by 18.0-27.2% in 2050 and 20.6-61.6% in 2100, and damage costs are predicted to increase from 29.7-50.8 billion KRW in 2050 to 35.7-116.1 billion KRW in 2100. Sea mustard production is projected to decrease by 24.5-37.2% in 2050 and 24.0-34.5% in 2100, with similar damage costs of 41.1-61.8 billion KRW and 41.1-58.6 billion KRW, respectively. These damage costs are expected to occur in the short term as damage caused by fishery disasters such as high temperatures, and in the long term as a decrease in production due to changes in aquaculture sites. Therefore, measures such as strengthening the forecasting system to prevent high-temperature damage, developing high-temperature-resistant varieties, and relocating fishing grounds in response to changes in aquaculture sites will be necessary.

PURPOSES : This study proposes a method for comparative analysis, based on geographic information systems (GIS), that can be used when introducing demand-responsive transit in areas where public transportation is not available. METHODS : To analyze areas where public transportation is neglected, bus stop location information, building location information, and administrative district boundary data for the census were acquired. Geocoding was used for address-based raw data to create a spatial database. Based on the collected data, the proportion of households separated by a certain minimum distance from a bus stop was aggregated and constructed through near analysis. When introducing a demand-responsive transit system, the operational cost was calculated and compared with the existing city bus transportation cost. RESULTS : Results show that the operating costs of introducing demand-responsive transit can be compared and analyzed using the proposed method, for a case study of Daejeon Metropolitan City. CONCLUSIONS : It is economically efficient to avoid the entry of route buses and introduce demand-responsive transit in areas isolated from public transportation where the number of people getting on and off is extremely low.

홍잠은 숙잠(熟蠶)을 수증기로 익혀서 인간이 섭취할 수 있도록 제조한 다양한 건강 증진 효과가 있는 천연 건강 식품이다. 현재 표준 제조 방법은 수증기로 찐 홍잠을 보관과 판매의 편의를 위하여 급속 냉동하여 동결 건조를 진행하는 것이다. 그런데, 홍잠을 동결 건조하는 과정은 많 은 시간과 비용을 필요로 하여 홍잠 제품 가격의 인상 요인으로 작용하고 있다. 본 연구에서는 홍잠을 수증기로 찐 후 바로 균질 액으로 제조하여 분무 건조하면 분말 제조 비용을 절감할 수 있음을 발견하였다. 그리고 홍잠 균질 액에 식용 단백질 분해 효소를 첨가하여 분해시킨 후, 단 1회의 분무 건조로 제품을 제조할 수 있는 방법을 개발하였다. 특히 홍잠 균질 액이나 효소 분해 홍잠 균질 액은 바로 액상이나 젤리 형태로 일반 또는 환 자용 특수 의료 용도 식품에 활용이 가능함을 보여주었다. 본 연구에서는 생산비용이 감소된 홍잠의 가공 방법을 제안하며 이는 제품 생성의 단가 를 낮추어 제품의 대중화와 양잠 농가의 연관산업 육성을 불러올 것으로 기대된다.