• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.952-959
• /
• 2022

Active construction work zones will result in longer travel time and/or longer travel distances for road users because of reduced speed limits and/or detours. This results in increased fuel consumption and increased emissions of harmful gases such as Carbon Monoxide (CO), Nitrogen Oxides (NOx), and Sulfur Oxides (SOx), which causes discomfort to the environment and road users around the work zone. The impact of such emissions should be considered while designing work zones or determining the number of days the roadway will be allowed to be closed partially or fully. This study develops a methodology to compute additional road user costs associated with such work zones. To achieve this goal, a) an extensive literature review is conducted, b) a framework to compute emission cost is developed, c) emission rates are computed for all counties (95) of the state of Tennessee, and d) a case study is conducted to demonstrate the use of the framework to estimate the additional impact of emission because of the work zone. For the case study conducted, the emission cost was computed to be $10,653.60 for the duration of the project. State DOTs can account for such road user costs while selecting contractors using A+B bidding. Accounting for such impact of emission will also indicate the agency's willingness to consider sustainability as a part of the business practices.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.64 no.4
• /
• pp.297-302
• /
• 2015

Replacing a manual switch installed in a feeder for a distribution system with an automatic one increases the reliability of the electric power system. This is because the automatic switch can shorten the duration of a fault the customer experiences by splitting the faulty section faster than the manual one does. However, improving the reliability of the distribution system may increase investment costs. Here, the investment costs include automatic switch cost, replacement work cost and labor cost. For this reason, importance should be attached to the proper balance between the increase of the investment costs and the improvement of the reliability of the distribution system. This article analyzed reliability index and economics when manual switches installed in a feeder (RBTS Bus2 model) was replaced by automatic ones. In addition, it attempted to draw the optimum rate of automation of manual switches by automatic ones using the GRG optimization method, considering the current economic requirements.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.115-118
• /
• 2009

Life time and number of use of liquid propellant rocket engine (LRE) should be carefully defined since those are crucial parameters affecting development costs and period. The present study surveyed the development and qualification records of LRE for space launch vehicles, especially concerning about test numbers and duration. It was shown that a single engine for expendable launch vehicle is tested with tens of ignition and several times duration of flight at least.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.608-615
• /
• 2022

Construction projects are large-scale projects that require extensive construction costs and resources. Especially, scheduling is considered as one of the essential issues for project success. However, the schedule and resource management are challenging to conduct in high-tech construction projects including complex design of MEP and architectural finishing which has to be constructed within a limited workspace and duration. In order to deal with such a problem, this study suggests resource and sequence optimization using constraint programming in construction projects. The optimization model consists of two modules. The first module is the data structure of the schedule model, which consists of parameters for optimization such as labor, task, workspace, and the work interference rate. The second module is the optimization module, which is for optimizing resources and sequences based on Constraint Programming (CP) methodology. For model validation, actual data of plumbing works were collected from a construction project using a five-minute rate (FMR) method. By comparing actual data and optimized results, this study shows the possibility of reducing the duration of plumbing works in construction projects. This study shows decreased overall project duration by eliminating work interference by optimizing resources and sequences within limited workspaces.

• Journal of the Korean Home Economics Association
• /
• v.39 no.11
• /
• pp.129-144
• /
• 2001

In spite of rapid sociocultural changes and an increase in the number of nuclear families in recent years, quite many families in Korea still have taken the extended family form where daughter-in-law provides care for the elderly parents. Even though the nature of the inter-generational relationship in Korea is reciprocal in many regards, most of the studies looked at the burden or costs of coresidence with the elderly parents while relatively little attention has been given to the positive side of the coresidence. This study is an attempt to fill this gap in the area. The purpose of this study is to examine not only the costs but also benefits of the coresidence with the elderly parents. We also explore whether there is a rural-urban differences in costs and benefits of coresidence and related factors. For the purpose, data were gathered from 876 daughters-in-law of three generational family both in rural and urban area, using structured questionnaire. The statistical methods used for data analysis were descriptive statistics, cross tables, and regression analysis with SPSS/PC+ program. The major findings of this study were as follows: Marital and economic status of the elderly parents, age, job status and filial responsibility attitude of caregiver, sibling support, and coresidence duration were the significant variables predicting the level of perceived benefits. Marital status of elderly parents, income, job status, educational level, and filial responsibility altitude of caregiver, residence region affected the level of perceived costs. Rural-urban differences are found in many aspects of coresidence experiences and related factors. Rural caregivers receive higher level of the sibling support, have more traditional final responsibility altitude and perceived less costs and more benefit than urban caregivers. There also are differences in the factors influencing the level of perceived costs and benefits between rural and urban area. Level of sibling support and final responsibility attitude have significant impact on both the perceived costs and benefits. But there are differences in terms of that perceived costs and benefits of urban caregivers are affected by job status of caregivers while those of rural caregivers are affected by educational level of caregivers and marital status of elderly. The results confirm that Korean caregivers experience both positive and negative aspects of coresidence and shows that the nature of the inter-generational relationships differ between rural and urban Korea.

• Culinary science and hospitality research
• /
• v.19 no.1
• /
• pp.42-56
• /
• 2013

This study showed that a sales executive officer, a founder of foodservice, and marketing methods and activities influence the duration of business and business performance. The hypotheses of the study are as follows. First, a foodservice business will influence marketing management. Second, marketing management will influence business performance. Third, founding a foodservice business influences business performance. Fourth, marketing management will influence the duration of business. Fifth, business performance will influence the duration of business. As a result, all the hypotheses are adopted. Consequently, business methods such as marketing activities and costs should be continually studied to improve management, and founders and managers should invest in marketing management in various ways.

• Journal of Korea Port Economic Association
• /
• v.27 no.3
• /
• pp.65-90
• /
• 2011

Private stevedoring companies are leasing and operating the container terminals of the Busan Port. The total amount of lease fees private stevedoring companies paid in 2010 reached 161 billion wons, an approximately 66 percent of the total revenue of the Busan Port Authority(BPA). In other words, lease fees are the most important revenue source for BPA. However, the lease fee assessment system of Busan container terminals goes against the principle of equity due to different assessment methods and criteria adopted by each container terminal. Therefore, the purpose of the study is to analyze the systematic problems of the lease fee assessment system that is used at Busan container terminals, and propose a new standardized scheme with a case study on the new system. In order to standardize the assessment system, the assessment methods need to be simplified by using the Discounted Cash Flow(DCF) method. In addition, the assessment criteria such as assessment duration, discount rates, price indexes, estimated container throughputs, sales unit price per TEU, operation costs, including labor costs, need to be standardized as well. The new standardized assessment system can be applied to estimate lease fees for new terminals. However, for existing terminals to run the new system, factors such as assessment duration, discount rates, price indexes, estimated container throughputs, investment and re-investment costs, and maintenance & repair costs of the new system should be changed slightly.

• Quality Improvement in Health Care
• /
• v.24 no.2
• /
• pp.15-25
• /
• 2018

Purpose: To compare the Appropriateness of abdominal CT to abdominal radiography as an imaging modality in terms of the diagnostic value, medical costs and decision making times for patients presented to the emergency department with nontraumatic abdominal pain. Methods: This study used the records of 530 cases presented to the emergency department(ED) with nontraumatic abdominal pain from February to March 2012. Imaging modalities were categorized into abdominal radiography and CT (radiography first or CT first) or radiography alone or CT alone. The diagnostic value, total medical costs and effect on decision making time of the each imaging modalities were compared. Especially, in retrospective review, to evaluate the predictability of the abdominal radiography, alit was assumed that all the 530 cases performed that exam as initial imaging. Results: Among 530 cases, 255 cases underwent abdominal radiography only, 28 cases underwent abdominal CT only and the remnant 247 cases underwent abdominal CT with plain abdominal radiography. The diagnostic value was higher in the cases with abdominal CT (268/275, 97.5%) than in the cases with plain abdominal radiography (19/255, 7.5%).The number of cases predicted by abdominal radiography only as initial imaging were 39/530 (7.4%). In cases where the patients performed the abdominal CT as the first imaging modality thereby omitting the abdominal radiography, the total diagnostic imaging fee was lower than in cases with plain abdominal radiography first followed by the abdominal CT (277,140 vs. 284,226(mean, Korean Won)). Although diagnostic value of the plain abdominal radiography as first imaging modality was lower than the abdominal CT, Decision making time, average duration of hospital stay was longer and the total medical costs was higher than abdominal CT. Conclusion: As an imaging modality in the ED for patients with acute nontraumatic abdominal pain, plain abdominal radiography is an avoidable procedure when viewed in terms of the diagnostic value and total medical costs and decision making times comparing with abdominal CT.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.2
• /
• pp.195-204
• /
• 2017

Objective : This 2009-2011 nation-wide study of adult Koreans was aimed to provide characteristics, medical utilization states, and survival rates for newly diagnosed patients with primary nonmalignant and malignant spine tumors. Methods : Data for patients with primary spine tumors were selected from the Korean Health Insurance Review and Assessment Service database. The data included their age, sex, health insurance type, co-morbidities, medical cost, and hospital stay duration. Hospital stay duration and medical costs per person occurring in one calendar year were used. In addition, survival rates of patients with primary malignant spine tumors were evaluated. Results : The incidence rate of a primary spine tumor increased with age, and the year of diagnosis ($p{\leq}0.0001$). Average annual medical costs ranged from 1627 USD (pelvis & sacrum & coccyx tumors) to 6601 USD (spinal cord tumor) for primary nonmalignant spine tumor and from 12137 USD (spinal meningomas) to 20825 USD (pelvis & sacrum & coccyx tumors) for a primary malignant spine tumor. Overall survival rates for those with a primary malignant spine tumor were 87.0%, 75.3%, and 70.6% at 3, 12, and 24 months, respectively. The Cox regression model results showed that male sex, medicare insurance were significantly positive factors affecting survival after a diagnosis of primary malignant spine tumor. Conclusion : Our study provides a detailed view of the characteristics, medical utilization states, and survival rates of patients newly diagnosed with primary spine tumors in Korea.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.22 no.4
• /
• pp.377-386
• /
• 2019

Purpose: Percutaneous liver biopsy (PLB), a diagnostic procedure to identify several hepatobiliary disorders, is considered safe with low incidence of associated complications. While postoperative monitoring guidelines are suggested for adults, selection of procedural recovery time for children remains at the discretion of individual operators. We aim to determine if differences exist in frequency of surgical complications, unplanned admissions, and healthcare cost for children undergoing outpatient PLB for cohorts with same-day vs. overnight observation. Methods: We performed a retrospective cohort study in children 1 month to 17 years of age undergoing ultrasound-guided PLB from January 2009 to August 2017 at a tertiary care, pediatric referral center. Cohorts were defined by postprocedural observation duration: same-day (${\leq}8$ hours) vs. overnight observation. Outcomes included surgical complications, medical interventions, unscheduled hospitalization within 7 days, and total encounter costs. Results: One hundred and twelve children met study criteria of which 18 (16.1%) were assigned to same-day observation. No differences were noted in demographics, anthropometrics, comorbidities, biopsy indications, or preoperative coagulation profiles. No major complications or acute hospitalizations after PLB were observed. Administration of analgesia and fluid boluses were isolated and given within 8 hours. Compared to overnight monitoring, same-day observation accrued less total costs (US $992 less per encounter). Conclusion: Same-day observation after PLB in children appears well-tolerated with only minor interventions and complications observed within 8 hours of procedure. We recommend a targeted risk assessment prior to selection of observation duration. Same-day observation appears an appropriate recovery strategy in otherwise low-risk children undergoing outpatient PLB.