PURPOSES : This study aimed to secure the work space in alarm valve rooms to ensure stable working conditions for the engineers. METHODS : We analyzed situations where alarm valve room work spaces were inadequately secured posing a problem. Using the Ovako working posture analysis system (OWAS) method, we measured the body size of adult male technicians and their tools to analyze the actual space needed for them to maintain a healthy posture while working. On this basis, we proposed regulations governing workspace size and acceptable durations for unstable body postures. RESULTS : By measuring valve room work space and technician body size, we found that the workspace was inadequate for technicians. Applying OWAS showed that securing more space in the valve room improved the construction stability. CONCLUSIONS : Regulations on valve room size and appropriate work space for technicians will improve construction and inspection stability. This reduces the probability of poor construction and inadequate inspection, increasing the reliability of the firefighting facility system.
Safe operation of freight vehicles is an important issue for drivers, cargo, and other road users. In particular, the center of gravity of a freight vehicle is directly related to the stability of the vehicle, and this can fluctuate in real time depending on weight changes. Every time a freight vehicle loads or unloads cargo, its center of gravity changes, and these changes greatly affect the risk of vehicle rollover. We researched a continuous center of gravity measurement system for freight vehicles for safe driving.
본 연구는 실봇을 병용한 인지강화 프로그램이 주관적 기억력 저하를 호소하는 노인의 인지기 능, 우울 및 치매예방행위에 미치는 효과를 알아보고자 하였다. 대상자는 경기도 성남시에 거주하는 노인 17명을 대상으로 복지관에서 수행되었다. 실봇과 인지강화를 병용한 총 20회기 프로그램을 개발하여 적용 하였으며 중재 전과 후에 한국 몬트리올 인지평가(K-MoCA), 우울(GDS), 치매예방행위(DPB)를 평가하였 다. 연구결과, 실봇을 병용한 인지강화 프로그램은 노인의 인지기능(t=-4.49, p<.001), 우울(t=2.58, p=.023)에서 통계적으로 유의한 차이가 있었다. 따라서 실봇을 병용한 인지강화 프로그램이 노인의 인지기 능 향상 및 우울 완화에 유용한 프로그램이 될 것으로 기대된다.
농업기계는 다양한 환경과 작물을 대상으로 작업을 수행하기 때문에 농업기계의 설계와 개발은 실 작업 부하를 고려하여 수행되어야 한다. 따라서 본 연구에서는 식용 옥수수 수확기의 실 작업 부하를 계측하기 위해 식용 옥수수 수확 시험을 수행하였다. 또한, 계측된 부하 데이터를 이용하여 수확기 내 기어박스 요소들의 강도 및 수명을 평가하기 위한 부하 스펙트럼을 구축하였다. 부하 스펙트럼은 기어박스의 구성요소 중 기어와 베어링에 적용 가능한 하중 지속 분포와 기어와 베어링을 제외한 축, 하우징, 캐리어 등에 적용 가능한 부하 스펙트럼으로 나누어 구축하였다. 본 연구를 통해 구축된 하중 지속 분포 및 부하 스펙트럼은 식용 옥수수 수확기의 기어박스 강도 및 수명 평가뿐만 아니라, 기어박스의 설계 하중으로도 활용이 가능할 것으로 보인다.
PURPOSES : The purpose of this study is to present a cross section suitable for low-traffic road pavement considering the environmental characteristics of Vietnam.
METHODS : The behavior of the pavement with respect to the axial load was numerically analyzed using the nonlinear finite element method. The elastic-plastic material model was applied to material properties such as subgrade, sub-base layer, and base layer, and whether the material yielded was determined. In order to evaluate the adequacy of the cross section of the Vietnamese low-traffic pavement, it was compared with the KPRP Lv 3 road pavement section. And it was compared with the newly proposed MAST composite Pavement. The design life of each pavement section was calculated using the results obtained from the pavement structural analysis.
RESULTS : The cross section of the Vietnamese low-traffic road pavement, KPRP lv3, MAST composite Type1 road pavement did not satisfy the design criteria for fatigue cracking and rutting. MAST composite Type2 was analyzed considering CTAB having 100mm and 150mm thickness and compressive strength of 5MPa, 10MPa, 15MPa and 20MPa, and all of them satisfied the design criteria.
CONCLUSIONS : The low-traffic road pavement section in Vietnam currently used is judged to be inappropriate, and the MAST Composite type 2 proposed in this study is evaluated as an appropriate alternative. Further studies such as field application are needed in the future.
For thousands of years, there have always been many disputes over the interpretation of the word JianShi (練實) in ZhuangZi Qiushui (《莊子·秋水》). The explanations about JianShi (練實) such as Bamboo fruits (竹實), neem fruits (楝實), white and pure fruit, and so on, but they are all debatable. The theory of “Bamboo fruits” (竹實) has no connections with the word form, which is quite abrupt and puzzling. The theory of “neem fruits”(楝實) is unreasonable and does not accord with the literal meaning of ZhuangZi Qiushui (《莊子·秋水》). The theory of “white and pure fruit” is contrary to the Ancient Chinese culture. Combined with the word form of JianShi (練實) and the literary meaning of Zhuangzi Qiushui (《莊子·秋水》), this paper holds that “練” and “揀” have the same meaning (selection), JianShi (練實) is JianShi (揀實) which means “Selected high-grade fruits”.
The vibration control device such as the damper can be used to reinforce the seismic performance of structures. The damper is activated by the deformation of structures during earthquake; however, the deformation of structures is extremely small, causing difficulty in using the damper. Therefore, there is a need for a method capable of amplifying small deformities and transmitting them to the damper. The purpose of this paper is to develop and evaluate a displacement amplification seismic system using cable-pulley. The appropriate cable was selected through a cable tensile performance test and the results of the frame experiment were compared with theoretical displacement amplification ratio values. As a result, it may be said that the proposed system using cable-pulley is useful for displacement amplification.
PURPOSES: This study presents the results of the collection rate of various road debris dummies using Automated Road Debris Remover System(ROBOS), which is a newly developed automatic road-debris removal system. In addition, for traffic flow safety, appropriate safe deceleration distances for ROBOS are estimated using VISSIM.
METHODS: A total of 12 kinds of road debris dummies were selected based on the opinions of public agencies, and randomly placed on the road. Repeated tests were performed. The road debris dummies were placed on the center of the lane, the shoulders, and the median. During the test, the ROBOS running speed was maintained at 15 km/h for an approximately 10-km-long roadway, and the collection and loading process was performed five times under the same condition. For the simulations, the road debris was assumed to be placed on Lane 1 under different traffic conditions and grades. Multiple simulations were conducted, and the average values were used to obtain appropriate safe deceleration distances for ROBOS.
RESULTS: The dummies were considerably large and heavy, and the collection rate was very high for the very light dummy. The simulation results indicate that during debris collection using ROBOS, when the traffic volume is relatively low, the degree of change in traffic flow is high, and when the traffic flow rate is high, the risk of an accident is also considerable.
CONCLUSIONS : We demonstrated that the debris collection efficiency of ROBOS is very high when the brush-conveyor and vacuum are used simultaneously. Further, when the exact location of road debris on specific lanes and for specific traffic volumes is known, a safe deceleration distance is recommended.
본 연구는 역삼투 해수담수화 플랜트의 실 데이터 분석을 통해 에너지 소모를 줄이는 방안을 제안한다. 이를 위해 10,000m3/d 이상의 플랜트를 대상으로 70여개의 데이터를 수집하고 분석하였다. 역삼투 해수담수화 플랜트의 에너지 소모는 에너지회수장치 발전으로 인해 크게 감소하였으나 각 요인에 따라 다른 값을 보였다. 에너지 소모는 유입수 수질에 영향을 받고, 높은 수질의 생산수를 얻기 위해선 더 많은 에너지가 소모됨을 확인하였다. 또한, 플랜트 규모가 커지면 에너지 소모가 줄어든다고 알려져 있으나 반드시 그런 것은 아니며, 역삼투시스템 운영 시 에너지 소모가 최소가 되는 회수율이 있음을 알아냈다. 마지막으로 에너지 소모와 관련된 요인을 정리하고 이를 바탕으로 저에너지 소모를 위한 3가지 방안을 제시한다.
PURPOSES : The objective of this study was to evaluate the field applicability of chip seals using recycled aggregates by comparing performance between natural aggregates and recycled aggregates for chip seals.
METHODS : In order to check the performance of chip seals using recycled and natural aggregates, Bitumen Bond Strength (BBS) test, Vialit and bleeding tests were carried out. Cationic emulsions (RS(C)-2 and latex modified RS(C)-2L) were used in the tests. Granite aggregates were used as the natural aggregate and recycled aggregate from road wastes were used as the recycled aggregate. The aggregate was used with uniform gradation between 10 mm and 4.75 mm to clearly compare the performance difference between natural and recycled aggregates.
RESULTS : Test results showed that the aggregate retention was low for both natural and recycled aggregates when applying RS(C)-2 (unmodified emulsion), but there was almost no difference between them when applying RS(C)-2L and RS(C)-2L-1 (modified emulsion) in the Vialit test results. In the bleeding tests, there was no bleeding for both natural and recycled aggregates when applying RS(C)-2 and RS(C)-2L.
CONCLUSIONS: It was possible to apply chip seals using recycled aggregates in the field because the chip seals with recycled aggregates and RS(C)-2L (modified emulsion) showed aggregate retention similar to that of natural aggregates, and there was no bleeding.
This study aimed to determine the optimal harvesting time for wheat to make grain silage, in Honam region of Korea. We harvested wheat grain every third day from 30 to 42 days after heading (DAH). The moisture content decreased from 61.6% at 30 DAH to 42.8% at 42 DAH. Yield of wheat grain significantly increased from 30 to 42 DAH (p< 0.05). Yield at 39 DAH (3.46T/ha) was not significantly different from that at 42 DAH (p< 0.05). With respect to the feed value of wheat grain silage, the amount of crude protein, crude fiber, and crude ash was different by harvesting time (p< 0.05). However, the amount of total digestible nutrients (TDN) from 30 and 42 DAH was not significantly different. The pH of wheat grain silage from 30 to 42 DAH was between 3.8 and 4.5 and it was stable until 39 DAH (p< 0.05). The lactic acid content of wheat grain silage from 30 to 42 DAH decreased from 3.08% to 1.10%. With respect to moisture content, yield, feed value, and fermentation, the optimal harvesting time for wheat grain silage was 39 DAH.
본 논문은 18세기 후반 프랑스에서 시작된 무대 멜로드라마의 영향으로 낭송자와 한 악기 주자 또는 오케스트라가 함께하는 연주회 방식으로 동시대에 발생한 콘서트 멜로드라마에 대한 학문적인 관심에서 출발하여, 창작 및 수용에 있어서 최고의 시대였던 20세기 초 독일의 콘서트 멜로드라마와 당대 대표적인 작품인 실링스의 ⟪마녀의 노래⟫를 연구한 것이다. 20세기 초 독일의 콘서트 멜로드라마는 낭송 텍스트로 발라드를 선택하는 18세기부터의 전통을 따르고 있고, 19세기 동안 굳어진 기악 음악의 묘사적인 표현 기능 및 음악적 동기의 유기성을 극적인 작품으로의 완결성을 위해 더욱 발전시키는 한편, 낭송자의 뛰어난 표현력을 작품의 창작 과정에서 고려하는 새로움을 수용했다. 대표적인 작곡가는 리하르트 슈트라우스와 실링스로, 특히 실링 스는 콘서트 멜로드라마를 주요 장르로 정착시키고 예술성을 알리기 위해 노력했다. 실링스는 빌덴브루흐의 발라드 <마녀의 노래>를 텍스트로 선택하여 동명의 콘서트 멜로드라마를 창작하면서 낭송 텍스트로 선택한 발라드의 내용을 그대로 쓰는 소극성에서 벗어나 극적인 짜임 새를 위해 각색하고 고유의 방식으로 주도동기를 설정하고 적용하여 낭송과 기악 음악의 조화를 추구하는 한편, 기악 음악만의 자율적인 감정 표현도 필수적인 요소로 삼는 새로움도 시도함으로써 콘 서트 멜로드라마의 발전 가능성과 독립된 형태로서 음악사적인 의미와 가치를 충분히 지니고 있는 것을 확인하게 하였다.
The concern of fine particle (PM2.5) management of outdoor environments has been increasing due to its exposure and related health effects in Korea. As a result, PM2.5 standard in atmosphere environment was regulated in 2015. On the other hand, indoor PM2.5 standard has been required because most people spent their times in indoor environments. In this study, we measured the PM2.5 and PM10 concentrations both indoor and outdoor environments of public-use facilities such as underground stations, underground shopping centers, and nurseries for 24 hour with filter-weighing method in Seoul and Daegu. Measurement duration was from March to April in 2014 during the Asian dust period. At all measurements, indoor to outdoor (I/O) concentration ratios exceeded 1 except 1 day nursery in Daegu in spite of Asian dust period. The ratios of PM2.5 to PM10 concentrations ranged from 0.63 to 0.75 in indoor environments, and from 0.63 to 0.82 in outdoor, indicating that PM2.5 should be carefully managed in indoor environments as well as outdoor atmosphere.
PURPOSES: This study aimed to evaluate the appropriateness of safety with the standard for threshold zone luminance as specified in the Recommendation for Lighting of Traffic Tunnel, which has been widely adopted worldwide.
METHODS: A driving test of the subject in a full-scale road tunnel was conducted. The adaptation luminance and threshold zone luminance, which should be known for the driver to perceive an object within stopping sight distance, were obtained. These values were compared with the adaptation luminance and threshold zone luminance obtained by the existing reduced model test and tunnel lighting standard that has served as a guideline for the current threshold zone luminance standard.
RESULTS : According to this study, threshold zone luminance should be increased to at least 1.8 times the value proposed in the existing studies and to twice the domestic tunnel lighting standard (KS C 3703: 2014).
CONCLUSIONS : The threshold zone luminance proposed in this study differs largely from that obtained from indoor tests and from the current tunnel lighting standard used worldwide; this difference may be attributed to the fact that the indoor tests did not incorporate driving workload, non-uniformity of luminance distribution in terms of sight, and factors that reduce the visibility of the driver, such as the light reflected into the driver’s eyes. Hence, it is necessary to further review the factors that reduce the visibility of drivers approaching tunnels in order to determine the rational tunnel threshold zone luminance.
PURPOSES : The objective of this study is to evaluate the early adhesive characteristic of asphalt emulsions, including polymer-modified emulsions, for chip seals using the surface energy concept, the bitumen bond strength (BBS) test, and the Vialit test.
METHODS : Two general methods, the BBS test and Vialit test, were applied to investigate the bond strength and the aggregate loss, respectively. A new theory, the surface free energy (SFE) theory, was used to evaluate the adhesive characteristic between the emulsion and the aggregate. Based on the theory, the contact angles were measured, and then the surface energy components were calculated. Using those components, the work of adhesion (Wa) was calculated for each emulsion. To ensure reliable results, all the tests were performed under the same conditions, i.e., at 25 ℃ for 240 minutes of curing time. For the materials, three emulsions (CRS-2, CRS-2L, and CRS-2P) and one aggregate type (granite) were employed. RESULTS AND
CONCLUSIONS : Under the same conditions, the modified emulsions showed better adhesive characteristics and curing behaviors than the unmodified emulsions. In addition, there was no significant difference between the various modified emulsions. One of the important findings is that the analysis by Wa presents more sensitive results than other methods. The results of the Wa showed that the CRS-2P emulsion has the best adhesive characteristics. Consequently, the use of modified emulsions for chip seals could prevent aggregate loss and allow open traffic earlier.
An effective method for produce munitions effectiveness data is to calculate weapon effectiveness indices in the US military’s Joint Munitions Effectiveness Manuals (JMEM) and take advantage of the damage evaluation model (GFSM) and weapon Effectiveness Evaluation Model (Matrix Evaluator). However, a study about the Range Safety that can be applied in the live firing exercises is very insufficient in the case of ROK military. The Range Safety program is an element of the US Army Safety Program, and is the program responsible for developing policies and guidance to ensure the safe operation of live-fire ranges. The methodology of Weapon Danger Zone (WDZ) program is based on a combination of weapon modeling/simulation data and actual impact data. Also, each WDZ incorporates a probability distribution function which provides the information necessary to perform a quantitative risk assessment to evaluate the relative risk of an identified profile. A study of method to establish for K-Range Safety data is to develop manuals (pamphlet) will be a standard to ensure the effective and safe fire training at the ROK military education and training and environmental conditions. For example, WDZs are generated with the WDZ tool as part of the RMTK (Range Managers Tool Kit) package. The WDZ tool is a Geographic Information System-based application that is available to operational planners and range safety manager of Army and Marine Corps in both desktop and web-based versions. K-Range Safety Program based on US data is reflected in the Korean terrain by operating environments and training doctrine etc, and the range safety data are made. Thus, verification process on modified variables data is required. K-Range Safety rather than being produced by a single program, is an package safety activities and measures through weapon danger zone tool, SRP (The Sustainable Range Program), manuals, doctrine, terrain, climate, military defence M&S, weapon system development/operational test evaluation and analysis to continuously improving range safety zone. Distribution of this K-range safety pamphlet is available to Army users in electronic media only and is intended for the standing army and army reserve. Also publication and distribution to authorized users for marine corps commands are indicated in the table of allowances for publications.
Therefore, this study proposes an efficient K-Range Safety Manual producing to calculate the danger zones that can be applied to the ROK military’s live fire training by introducing of US Army weapons danger zone program and Range Safety Manual