• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.457-468
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• 2011

Recently, the non-vibration mass excavation method is used on sewage pipes and road construction sites in Jeju. However, a construction cost estimation based on the unit quantity does not provide a proper unit price. In this study, a comparison of the productivity of the standard quantity-per-unit costing method and the one of the work crew combination method was made based on the site monitoring of the non-vibration mass excavation method that is used in construction sites near Jeju. For this, data of 35 sites were collected: a regression equation was derived from the 30 data, and verification was carried out through the remaining 5 data. The analysis concluded that a day's workload is $16.43m^3$. In addition, a combination of the equipment considering the site conditions and the amount of labor, which varies with the number of work crew was obtained in order to estimate the construction cost of the work crew combination method. The construction cost was calculated based on the one-day workload ($16.43m^3$) derived from the regression analysis. The cost then was analyzed and compared with the standard quantity-per-unit costing method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.177-187
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• 2023

The Ship Safety Act prescribes matters necessary for the maintenance of seaworthiness and safe navigation of ships. In this regard, Article 10 of this Act requires shipowner to undergo occasional survey if he/she wants to temporarily change intends to modify the details entered in a ship survey certificate. Such measures are in accordance with the maintenance of the state of the ship after the ship inspection under Article 15 of this Act, and this Act includes "harbor construction work ship" under Article 39 Paragraph (1) of the Harbor Act. However, although the harbor construction work ship originally showed the same operating system as the barge, it was not applied to the Ship Safety Act and was registered and surveyed under the Construction Machinery Management Act. Then "Seokjeong No. 36" sinking accident in Ulsan on December 14, 2012, led to the amendment of the Harbor Act in 2016, and considering the fact that it was added to the Ship Safety Act and applied, there is a realistic limit to applying all the regulations stipulated in the Ship Safety Act to the harbor construction work ship. Accordingly, this study discusses the work characteristics through concept, registration, work area, survey regulations, application case of temporary alteration etc. of harbor construction work ships and controversial issues related to the scope of application of the Ship Safety Act of actual harbor construction work ships, and also the appropriate scope of "temporary alteration" among temporary inspections prescribed in Article 10 of the Ship Safety Act in consideration of the legislative purpose of incorporating harbor construction work ships into the survey subject to the Ship Safety Act in accordance with the revision of the Harbor Act.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4165-4176
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• 2014

Although agriculture has a long history, there has beena lack of consideration and interest in farmers. This paper considered the present condition of agriculture on anergonomic perspective using a literature review and suggestsdirections for afuture study to improve the work efficiency and safety-health of farmers. The results showed that the literature could beclassified 4 categories; the design of agriculture equipment, safety-health, safety management, and product design. The safety-health category contained the majority of papers with product design category containing the minority. In future, a study ofproduct liability probability, the design of a work and rest time, and clothes design against cold will be needed.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.334-341
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• 2008

Ballast track needs maintenance works because it is supported by the compressible trackbed and subgrade layers. Maintenance works are essential to secure riding comfort and extend the life cycle of it. The necessities of maintenance works are determined from track irregularities measured by EM120. Track irregularities is the results of the track deformation. Therefore, it is natural to evaluate the cause of it. This paper focuses on the points the track irregularities come from the trackbed and the subgrade. Nondestructive techniques, such as Ground Penetrating Radar (GPR) and Portable Falling Weight Deflectometer (PFWD) are applied to evaluate the trackbed conditions, ballast layer thickness and vertical track stiffness, in the test section 500m long of Gyungbu line. The trackbed investigation results are compared with the track irregularities measured by EM120 and maintenance works. Conclusively, it was found that some maintenance works were unnecessary on the test section.

• Korean Journal of Poultry Science
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• v.20 no.3
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• pp.141-149
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• 1993

In order to develop a poultry manure dryer, a pilot dryer was designed and drying experiments were conducted to investigate the drying characteristics of poultry manure. According to the results, the pilot dryer could be operated without any air pollution problems. When poultry manure was dried from 79.2%(w.b. basis) moisture content, the final moisture content ranged from 38.7% to 57.9% depending upon the drying conditions. The drying results showed that drying rate was 189.8~198.0 kg/h and moisture evaporation rate was 124.0~125.4kg-$H_2$O/L. For this drying, electricity requirement was 9.5~19.3 Wh/kg and fuel consumption rate was 6.9~9.3 kg-$H_2$O/L with 50.2~65.1% thermal efficiency.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.1-6
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• 2023

PE piping, which has advantages in terms of construction convenience and economy, is widely used for underground burial in the domestic urban gas field. These PE pipes use squeeze-off in many sites to block gas flow during maintenance and repair work. Squeeze-off refers to a method of compressing a PE pipe to block fluid flow, and damage may occur due to the nature of construction in which the pipe is deformed by physical force. In order to prevent damage to PE pipes due to squeeze-off, the main points to be reflected in the squeeze-off operation procedures such as proper compression range, use pressure, and diameter were derived through damage assessment and confidential test according to the compression rate. The compression experiment for PE pipe damage assessment was conducted while changing the compression rate (20%~40%), the pressure of use (2.8 kPa, 25 kPa, 70 kPa), and the pipe diameters (63 mm, 90 mm, 110 mm). As a result of damage assessment according to the compression rate, damage occurred in pipes with compression rates of 45%(110mm) and 73%(63mm), which are for analyzing the effect of excessive compression. In addition, the leakage test was conducted using Ar(argon) during the squeeze-off, and as a result of the experiment, leakage occurred under the conditions of 70kPa and 110mm of pipe. As a result of this study, it was confirmed that squeeze-off for airtightness should be carried out in pipes within a range not exceeding 25 kPa and 90 mm pipes, and the appropriate compression rate to prevent damage to PE pipes is 30%.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.7-12
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• 1977

In order to find out the optimum weeding date for growing barley in paddy field, several kinds of weeding dates and frequencies were made and compared. The results are summarized as follows: 1. As far as the weeding frequencies were fixed with one time, an immediate weeding after wintering resulted better barley grain yield and yield components by causing decreased yield of weed. 2. Maximum allowable date to be free from the weed competition were estimated as not late than February 10 or at most february 25. 3. It is considerable that the effect of weeding was continuously found till March 11 but no significant weeding effect was found when the weeding was done after April. 4. The competition of weed and barley was relatively so higher from February 25 to March 30 that the control during this period seemed to be very effective by causing little decrease in barley grain yield. 5. Major overdominant weeds observed in the paddy field for barley growing period were Alopecurus aequalis S., Stellaria alsine G., and Galium aparin L., in the order of degrees.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.1
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• pp.1-8
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• 2011

Efficient power management plays a crucial role to strengthen competitiveness in the market of portable mobile commodities. This paper presents a proactive power management technique, called by Energy-Aware Scheduling policY (EASY), to exploit the sleep time information of running applications. Different from previous power management approaches focusing on power conservation in standby mode, the proposed scheme characterizes each application program's operational characteristic in active mode by observing how long the task stays in sleep state of CPU scheduler. Based on the measured sleep time, the proposed EASY speculates an adequate CPU clock frequency according to the current CPU workload and scales the frequency directly to the predicted one. Experimental results show that the proposed scheme reduces the power consumption by 10-30% on average compared to traditional DPM approach, with a minimal impact on the performance overhead.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.412-412
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• 2023

정부는 2027년까지 식량자급률 55.4%를 달성하고, 채소·과실류 국내 공급 여력의 85% 수준을 유지하기 위한 적정 농지면적 150.0만ha가 필요하다고 추정하였다. 그리고 정부는 적정 면적 확보를 위해서 농지보전 목표가 포함된 중장기 기본계획을 수립할 예정이다. 이러한 식량자급률 달성과 채소 및 과실류 재배 면적 확보를 위해서는 논의 다각적인 활용 방안을 모색할 필요가 있다. 왜냐하면 최근 쌀 공급과잉 문제를 해결하기 위해 최근 '양곡관리법'이 정치적 이슈로 등장할 만큼 쌀 공급과잉 해소와 논 농지의 효율적인 활용에 대해 사회적 관심이 많다. 이러한 맥락에서 본 연구에서는 우리나라 최초로 논 배수 개선을 위해 지하암거가 설치된 경북상주시 공검면 일대를 대상으로 암거배수의 성과를 살펴보고 개선방안을 모색하였다. 이를 위해 본 연구에서는 지하암거 설치로 배수여건이 개선된 수혜농가 42명을 대상으로 심층면담을 실시하였다. 사례지역은 오태저수지를 기점으로 시작하는 공검소하천 양안에 넓게 위치하고 분지지형으로 하천보다 낮은 저지대로, 평상시·강수시 지하수위가 높아 습답이 형성되어 영농기계 사용이 어렵고, 일부지역의 경우 작물 파종, 수확을 하지 못하는 등 피해 발생하여 영농여건이 매우 불리한 지역이다. 이러한 배수불량을 개선하기 위해 수혜면적 55.6ha에 (지하)배수가 정비되었다. 이러한 배수 개선이 지역 영농에 미치는 효과는 다음과 같이 분석되었다. 첫째, 수혜구역 내 농가들은 배수불량으로 농기계 작업이 불편하고, 논의 습답을 제거하기 위해 해당 시설에 대한 필요성을 느끼고 있다. 또한 암거배수 시설로 인해 약 72% 농가들은 습답 개선의 효과가 있는 것으로 나타났다. 둘째, 전체 수혜농가의 약 72%는 암거시설로 인해 논의 습답이 개선된 것으로 나타났다. 특히, 암거시설로 인해 물빠짐이 개선되었고, 농기계 작업이 용이하게 되었다. 다만 사업 첫해에는 논을 파헤쳐 농기계가 빠지는 피해가 있었지만, 2차년도부터는 논이 정비되어 농기계 빠지는 피해는 없는 것으로 분석되었다. 셋째, 수혜 농가들이 느끼는 "습답 피해가 매우 있음"은 사업 시행 전 51.61%에서 사업 완료 후에는 4.17%로 급격히 감소하였다. 또한 "습답 피해가 전혀 없음"을 느끼는 농가는 사업 시행 전 3.23%에 불과했지만, 사업 완료 후에는 20.83%로 급증하였다.

• Korean Journal of Construction Engineering and Management
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• v.11 no.3
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• pp.125-133
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• 2010

Although work-efficiency of construction machinery is a critical factor for estimating its workable-quantity perunit time, the efficiency figure table presented in the Poom-Sam that is used for Construction Cost Estimation of public sectors in Korea is very subjective for practical usage. In order to suggest objective work-efficiency table for a Pump-Dredger, domestic and overseas documentary records were investigated and on-going construction sites were also visited. Moreover, actual work quantities collected from the site visits were compared with the ones calculated based on the Standard Measurement Methods used in Japan. The research found that the table can be revised by means of detailing down by several factors, namely project type, depth of soil, undersea-site shape, and condition on the sea for better estimation of its workable-quantity. The research will be the foundation for applying the rapid development of Construction Equipment and technology to the appropriate cost estimations and the ground work of related studies.