편의식 소비가 증가하는 식문화가 정착되면서 쌀의 소비형태가 전통적인 쌀밥에서 편의식 가공제품 형태로 변화되면서 떡류는 훌륭한 대체재로 자리 잡아가고 있다. 하지만 대부분의 떡은 소규모의 영세한 업체에서 제조되고 있으며 구입 후 별도의 조리과정 없이 그대로 섭취하므로 떡의 미생물학적 안전성에 대한 우려가 증가되는 추세이다. 따라서 본 연구는 떡류에서 발생하는 미생물학적 안전성을 개선하고자 소규모 업체의 떡류, 생산 환경 및 작 업자의 미생물 오염도를 조사하였다. 3가지 떡(가래떡, 인절미, 경단)을 선정하여 원료, 제조공정 및 제조환경에 대한 미생물 오염도를 측정한 결과, 6가지 원재료에서 일반 세균 3.76-4.48, 대장균군 2.21-4.14, B. cereus 1.02-1.15 log CFU/g 수준으로 검출되었고, E. coli는 검출되지 않았다. 떡의 제조공정별 오염도 분석결과, 세척과정 후 원재료의 일반세균, 대장균군 및 B. cereus의 오염도가 감소하였지만 불림, 분쇄공정에서 다시 증가하였고, 증자 후에는 3종류의 떡에서 모두 검출한계 이하의 수준을 보였다. 그러나 증자 이후 성형 및 냉각과정을 거치면서 오염도가 다시 증가하여 이 과정에서 냉각수 및 성형떡의 고물관리에 대한 주의를 시사하였다. 떡의 제조환경에 대한 미생 물학적 오염도 분석결과, 쌀 분쇄기 및 떡고물 작업환경에 대한 오염 수준이 높게 나타났으며, 성형기에서도 일반세균, 대장균 및 B. cereus가 검출되어 작업환경에서의 기구 및 제조설비 관리가 필요하였다. 제조설비 및 환경에서의 오염은 원재료와의 교차오염을 일으킬 수 있으므로 체계적인 세척 및 소독 등으로 미생물학적 위해를 감소시켜야 할 것으로 사료된다.

To enhance the effectiveness of the FMS (flexible manufacturing system), it is necessary for the manufacturing control system to be upgraded by integrating the cyber and the physical manufacturing systems. Using the CPPS (Cyber-Physical Production System) concept, this study proposes a 4-stage vertical integration and control framework for an aircraft parts manufacturing plant. In the proposed framework, the process controller prepares the operations schedule for processing work orders generated from the APS (advanced planning & scheduling) system. The scheduled operations and the related control commands are assigned to equipments by the dispatcher of the line controller. The line monitor is responsible for monitoring the overall status of the FMS including work orders and equipments. Finally the process monitor uses the simulation model to check the performance of the production plan using real time plant status data. The W-FMCS (Wing rib-Flexible Manufacturing Control & Simulation) are developed to implement the proposed 4-stage CPPS based FMS control architecture. The effectiveness of the proposed control architecture is examined by the real plant’s operational data such as utilization and throughput. The performance improvement examined shows the usefulness of the framework in managing the smart factory’s operation by providing a practical approach to integrate cyber and physical production systems.

The concentrations of volatile organic compounds (VOCs) and odor-inducing substances were measured using selected ion flow tube mass spectrometers (SIFT-MS) and a drone equipped with an air quality monitoring system. SIFT-MS can continuously measure the concentration of VOCs and odor-inducing substances in realtime without any pre-treating steps for the sample. The vehicle with SIFT-MS was used for real-time measurement of VOC concentration at the site boundaries of pollution sources. It is possible to directly analyze VOCs concentration generated at the outlets by capturing air from the pollution sources with a drone. VOCs concentrations of nine spots from Banwol National Industrial Complex were measured by a vehicle equipped with SIFT-MS and were compared with the background concentration measured inside the Metropolitan Air Quality Management Office. In three out of the nine spots, the concentration of toluene, xylene, hydrogen sulfide, and methyl ethyl ketone was shown to be much higher than the background concentration. The VOCs concentrations obtained using drones for high-concentration suspected areas showed similar tendencies as those measured using the vehicle with SIFTMS at the site boundary. We showed that if both the drone and real-time air quality monitoring equipment are used to measure VOCs concentration, it is possible to identify the pollutant sources at the industrial complex quickly and efficiently check sites with high concentrations of VOCs.

We developed a wet scrubber by applying cyclone flow to the gas flow and using a spiral filter structure. While the size of a new scrubber was about half that of a conventional scrubber, the device showed relatively high efficiency in pollutants removal such as particulate matter and compounds inducing odor. The new scrubber installed in a plating industry showed a higher removal efficiency of about 5% for dust, about 23% for hydrogen chloride, and about 23% for sulfur dioxide compared to the conventional scrubber. Plurality of tubes in the spiral filer housing are arranged to be vertically shifted from each other. Because the upward residual gas does not directly rise vertically, the residence time of gas between the filter plates is extended. Thus, the purification efficiency of the pollutants was enhanced in the new scrubber. In addition, the new scrubber developed in this study is more cost effective because the cost saving in manufacturing it compared with a conventional scrubber increases with increasing the size of equipment. It is expected that a scrubber with better dust collecting efficiency can be obtained by carrying out a study in connection with facilities capable of controlling acidity of washing water.

Tungsten trioxide (WO3) is a promising candidate as a photocatalyst because of its outstanding electrical and optical properties. In this study, we prepare WO3 thin films by electrodeposition and characterize the photocatalytic degradation of methylene blue using these films. Depending on the voltage conditions (static and pulse), compact and porous WO3 films are fabricated on a transparent ITO/glass substrate. The morphology and crystal structure of electrodeposited WO3 thin films are investigated by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. An application of static voltage during electrodeposition yields a compact layer of WO3, whereas a highly porous morphology with nanoflakes is produced by a pulse voltage process. Compared to the compact film, the porous WO3 thin film shows better photocatalytic activities. Furthermore, a much higher reaction rate of degradation of methylene blue can be achieved after post-annealing of WO3 thin films.

This study deals with the case study on the pallet quantity determination problem for the flexible manufacturing system producing 32 different types of aircraft wing ribs which are major structures of an aircraft wings. A Korean company has constructed the WFMS (wing rib flexible manufacturing system) that is composed of several automated equipments such as the 5-axis machining centers, the RGV (rail guided vehicles)s, the AS/RS (automated storage and retrieval system), the loading/unloading stations, and so on. Pallets play a critical role in the WFMS to maintain high system utilization and continuous work flow between 5-axis machining machines and automated material handling devices. The discrete event simulation method is used to evaluate the performance of the WFMS under various pallet mix alternatives for wing rib manufacturing processes. Four performance measures including system utilization, throughput, lead-time and work in process inventory level are investigated to determine the best pallet mix alternative. The best pallet mix identified by the simulation study is adopted in setting up and operating a real Korean aircraft parts manufacturing shop. By comparing the real WFMS’s performances with those of the simulation study, we discussed the cause of performance difference observed and the necessity of developing the CPS (cyber physical system).

This study was an attempt to analyze the basic analytical characteristics of octanal and nonanal compounds by TD and GC/FID system. The basic analysis (linearity, precision, MDL: method detection limit) showed similar results for VOCs in terms of QA/QC results with the same analysis system. Also, the results are sufficiently satisfy the QA/QC of the Korean odor analysis standard method. When using a polyester aluminum bag, the amount of loss was found to be about -2% to 7%. Adjusting the relative humidity and loss trend with the passage of time, the loss amount is found to be only a trace amount. With the exception of the styrene compound, all volatile organic compounds have a tendency to decrease slightly. Similar results were shown from Octanal and Nonanal. As a result, Octanal and Nonanal compound’s adsorption amount by the polyester aluminum bag was a quite small. The relative humidity and other compounds appear to be significantly unaffected by Octanal and Nonanal.

This study attempts to investigate the impact of pollution by VOCs at schools located around Shihwa national industrial complex. Schools around the Shihwa national industrial complex were divided into two categories based on location, with five schools located near the industrial complex and five schools located near housing development. Samples of the indoor air and the outdoor air were collected from each classified school and analyzed to evaluate the impact of the industrial complex on each school through a comparison and to find the correlation between them. In combination with this, this study attempted to conduct comparative evaluations of the schools in which there might be relatively higher indoor air pollution since new construction and extension or remodelling had recently been carried out with other schools. The samples collected from 10 places in total were analyzed, using GC/MS. TVOCs, and individual component of VOCs, were detected in the schools near shihwa national industrial complex at higher levels than in the schools nearby housing development. TVOCs were detected at the schools in the industrial complex st levels of 166.5 μg/m3, that is, about 1.5 times higher than the level detected at the schools outside the industrial complex. TVOCs were found in the indoor air of the schools that had been extended or remodelled less than 3 years ago at levels of 188.8 μg/m3, while in schools where more than 3 years had passed since extention or remodelling they were found at levels of 97.5 μg/m3, meaning they were about 1.9 times higher in schools in the first 3 years.

The purpose of this study is to develop a scrubber wastewater cleaning system to improve the efficiency of odor reduction. We evaluated the changes in scrubber wastewater quality and odor reduction efficiencies before and after applying the pilot system. We determined that it was possible to extend the replacement cycle by two times or more considering the turbidity change and organic removal efficiency. Butyraldehyde, a major odor-causing substances in the exhaust gas of the target facility, is soluble in water. As a result, the odor reduction efficiency was improved by removing the butyraldehyde in the scrubber wastewater. Economically, it is possible to save about 12 million won per year. Thus, it is necessary to keep scrubber wastewater clean in order to improve the deodorization efficiency and reduce the cost of disposal.

This study tried to survey air quality inside and outside the schools where are located in about 5km of industrial complex targeting aldehyde, PM10, PM2.5. Also, the aim was also to examine both a change in indoor air after 3 years and within 3 years of addition and improvement, and a change according to season. It collected specimens at totally 20 places. Aldehyde was analyzed through HPLC. PM10 and PM2.5 were measured by using Met One 831. Formaldehyde and Acetaldehyde were detected with 42.1 μg/m3 and 5.7 μg/m3 at the school where is located inside 5km of the industrial complex, and were detected with 55.0 μg/m3 and 6.8 μg/m3 at the school where is located outside 5 km. This could be confirmed to have been detected more highly in the indoor air than the outdoor air regardless of the distance from the industrial complex. Most substances were indicated to be higher by about 150% in the indoor air within 3 years than the indoor air following 3 years of addition and improvement. However, PM10 and PM2.5 were measured with 32.6 μg/m3 and 14.9 μg/m3 after 3 years and were gauged with 22.4 μg/m3 and 14.2 μg/m3 within 3 years. Seeing a seasonal change, Formaldehyde and Propionaldehyde were detected with 5.5 μg/m3 and 1.0 μg/m3 in spring, 7.7 μg/m3 and 1.6 μg/m3 in summer, and 8.3 μg/m3 and 1.9 μg/m3 in autumn. This could be confirmed the tendency of growing according to season.

Almost all buildings and infrastructures made of advanced composite materials are fabricated without proper design. Unlike airplanes or automobiles, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long span bridges. People try to build 100-story buildings or several thousand meter long span bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design. Concept optimization, Simple method of analysis, Folded plate theory, Size effects in failure, and Critical natural frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method. In this paper, concept optimization and folded plate theory are presented for practicing engineers.

The special orthotropic plate theory is used for analysis of panels made of plate girders and cross beams. The cross-sections of cross-beams are WF types. The result is compared with that of the beam theory. According to the numerical examination given in this paper, the result by the plate theory is 2.43 times stiffer than that of beam theory.

In this paper, the relation between the applied load distribution and the natural frequency of vibration of some structural elements is presented. In this paper, the effects of the loading sizes on the natural frequency of vibration of some structural elements is presented. Many junior engineers get confused on such relations. This method extended to two dimensional problems including advanced composite laminated structures. It is hoped that this paper gives some guideline to such junior engineers.

Recently, odor and white smoke emitted from textile industry has emerged as a social problem. Most of pollutants from textile industry is due to the emissions from tenter facility, and in many case wet scrubber is widely used for treating this waste gas from tenter facility. However, it is still difficult to improve the environment of textile complex because of low treatment efficiency. For this reason, we carried out the EFC (Electric Fume Collector) pilot test (50 CMM) for removing odorous substances from waste gas emitted from tenter facility. EFC is a kind of wet electrostatic precipitator. As a result of this study, pollutants and white smoke were eliminated effectively and quite large amounts of oil could be recovered.

In this study, Seoul Terminal (Gangnam Express Bus Terminal, South Terminal, East Seoul Terminal) from a one-way mileage 200 ㎞ or more long-distance express bus and coach routes to target indoor air quality (CO₂, PM10) to investigate the interior air quality levels investigated. If the former route of PM10 in the study indoor air quality guidelines, LEVEL1, 2 (150 ㎍/㎥, 200 ㎍/㎥) although has been surveyed. PM10 concentrations of Bus 14.9 ㎍/㎥ the intercity bus (12.1 ㎍/㎥) was higher than the survey. Summer is the season of high-speed bus, CO₂, estimated at 10 before measurement guidelines from the line Ministry Level 1 (2,000 ppm) and Level 2 (3,000 ppm) meet, whereas the measurement results from Seoul to Daegu Summer off season (2,589 ppm), Seoul to Busan (2,332 ppm) from the Ministry of Environment guidelines between Level 1 (2,000ppm) were investigated to exceed. Coach Bus in Seoul and captures the summer season (2,793 ppm), Seoul to Yangyang (3,896 ppm), Seoul and Imsil (3,739 ppm) and the Ministry of Environment guidelines on Route 3 Level 1 (2,000 ppm) and Level 2 (3,000 ppm) was surveyed in excess. Based on these results, public transport operators or manufacturers of public transport vehicles properly maintained to the Public Transportation System air quality by providing guidelines for managing the use of public transport and protect people"s health and help provide a comfortable service This is expected to be able to.

On-line shopping mall has become a powerful marketing tool recently. On-line shopping malls provide information for consumers about goods and influence the decision-making process of purchasers. Therefore many local government made on-line shopping malls for advertising agricultural production in the region. However, in the face of problems related with effectiveness on shopping mall management, most of on-line shopping malls has been managing by private sector actually. This study aims to propose the plans for development of the on-line shopping malls. For this purpose, this study investigated current management status of the shopping malls and conducted case study on-line shopping malls.

본 논문에서는 철근콘크리트 슬래브교를 복합적충판 이론으로 해석하였 다. 철근콘크리트 슬래브교의 해석에 있어 단변의 기하학적 , 물리적 특성이 중립축을 중심으로 휩-연 계강성 B; j=O 이 고， DI6=D26=0 임을 고려하였다. 각각의 횡방향，수직방향 강재는 하나의 lamina로 간주하고，재료상수는 각각의 l amina의 흔합법칙 에 의해서 계산되었다. 단순지지된 철근콘크리트 슬래브교는 동분포하중과 축하중을 받고 있다 . 본 논문에서는 유한차분법과 특별직교이 방성 복합적충판 이론으로 해석하였다. 그 결과 특별 직교 이 방성 복합적충판 이론에 의한 해석값이 보 이론의 값에 근접함을 알 수 있었다 . 본 논문의 결과 가까운 장래에 학부정도의 실력을 가진 기술자가 철근콘크리트 슬래브교를 해석함에 있어 유용하게 사용 될 수 있다.

This research aims to examine consumers’ general types of information search and their unsatisfactory factors in purchasing agricultural products on electronic commerce and analyze consumers’ behavioral characteristics. As study subjects, 802 consumers who have visited the home pages of 14 households or companies, whose home pages are actively managed, were sampled. As a research tool, pop-up post and e-mail were used as research tools and questionnaires were asked three times. The date on research result were analyzed using SPSS 13 statistics package in terms of frequency, percentage, descriptive statistics, one-way ANOVA and correlation analysis.

The VOCs discharge characteristics of miscellaneous assembly metal manufacture & metal processing industries, in the SihwaㆍBanwol Industrial Complex, were analyzed according to detailed categories per industry, as based on the Korea Standard Industrial Classification, by comparing the conditions before and after the installation of process and prevention facilities. The average concentration of benzene was highest in the metal heat treatment industry (28921) whereas that of toluene was highest in the painting & membrane treatment industry (28923). In addition, with respect to prevention facilities, our evaluation proved that the decreased efficiency was worse for the discharge facilities of pollutants from the plating industry (28922) and painting & miscellaneous membrane treatment industry (28923), with some exceptions, while most facilities showed no decreased efficiency. Therefore, it is believed that an accurate survey of the conditions of administration/operation facilities will need to be conducted, and the decreased efficiency will also need to be evaluated so that adequate prevention facilities can be reviewed and selected.