Recently a biosafety level-3(BL-3) mobile laboratory has been set up for the virus scanning and vaccine development because of the COVID-19 pandemic. The study on air flow inlet and outlet location and its flow direction with ventilation in the mobile laboratory needs to prevent spread of COVID-19 virus because the COVID-19 virus is primarily transmitted to people through respiratory droplets and aerosol coming out as their coughing. This study is conducted on the air flow pattern optimization in BL-3 mobile laboratory with various design specifications of position of air supply & exhaust port and particle source. Air flow patterns of ceiling supply-exhaust and ceiling supply-bottom side exhaust with particle source were determined to compare the impact of the infection prevention. CFD simulation was used to analyze for two air flow patterns and particle source position. Numerical results showed that air flow pattern of air conditioning system with ceiling supply-exhaust in a row is more effective than that of ceiling supply-bottom side exhaust air flow pattern in terms of infection prevention in biosafety mobile laboratory.

대기오염물질 감축에 대한 국제적인 인식이 높아짐에 따라 친환경 선박에 대한 수요가 증가하고 있어 각국에서 전기추진선박 개발을 활발하게 수행하고 있다. 현재 전기추진선박에 대해서는 주로 전기추진시스템 및 전동기 연구를 주로 수행하고 있으며, 선박 관점 에서 전기추진시스템 및 배터리의 탑재를 고려한 국내 연안 차도선 개념설계 연구는 수행된 바가 없다. 본 연구에서는 배터리 차량 기반의 이동식 전원공급시스템을 주전원으로 하는 순수전기추진차도선의 개념설계 과정에서의 주요 고려사항에 대하여 검토하였다. 100척 이상의 국내 연안차도선의 제원을 분석하여, 요구사항 만족을 위한 선박의 주요제원 선정과 이동식 배터리 차량 탑재를 고려한 비손상, 손상 복원성능 검토를 수행하였고, 개념설계 과정에서 발생하는 문제의 원인분석을 통해 해결방안을 모색하였다.

Stone cutting process that it became with the tree, after fixing with the neck which is was fixed the stone in portable type transfer and department with cutting department which is in the process of operating and it transferred it was in the process of moving with the method which cuts with hour vibration where the stone will reach to the saw blade it was caused by, the raw materials waste and the inferior good which under the actual conditions which are disconnected from the default location of the stone are caused by soaking pit of the stone were under occurring. Consequently objective of this research currently the fixation stone cutter which is used from the stone processing and cutting enterprise about lower the productivity falls on a large scale with fixation, the raw materials loss to be many is sufficient the satisfactory degree of the enterprise considerably and to be insufficient in order the problem which is like this to solve the new cutting technical develop.

The purpose of this study is to analyze the adequacy of production capacity of the assembly process system of mobile bath vehicle’s top box panel and process design through a simulation analysis. Towards this end, the layout of the facility designed with pre-verification job using a simulation modeling and an experiment, and facility, logistics process, and personnel input method were made into a simulation model, and the design system’s adequacy was evaluated through an experiment. To produce 120 mobile bath vehicles annually, it was analyzed that 14 general workers and seven skilled workers were adequate through the experiment. It was also identified that three painting process lines carried out through outsourcing were adequate. Production lead time was 201.7 hours on average and it was 230 hours maximum. To meet customer delivery service level of 95% within the deadline when establishing a customer order and vehicle delivery plan, it was analyzed that more than 215 hours of lead time is needed minimum. If the process cycle time is reduced to 85% upon system stabilization and skillfulness improvement, it was analyzed that annual output of 147 vehicles can be achieved without additional production line expansion.

The leading source of occupational fatalities is a portable ladder in Korea because it is widely used in industry as work platform. In order to reduce victims, it is necessary to establish preventive measures for the accidents caused by portable ladder. Therefore, this study statistically analyzed injury death by portable ladder for recent 10 years to investigate the accident characteristics. Next, to monitor wearing of safety helmet in real-time while working on a portable ladder, this study developed an object detection model based on the You Only Look Once(YOLO) architecture, which can accurately detect objects within a reasonable time. The model was trained on 6,023 images with/without ladders and safety helmets. The performance of the proposed detection model was 0.795 for F1 score and 0.843 for mean average precision. In addition, the proposed model processed at least 25 frames per second which make the model suitable for real-time application.

A retractable bollard system has been used for the traffic control and protection of important facilities such as electric power plants, airports and government buildings etc. The power source of the driving unit of the conventional protective bollard system is on hydraulic or pneumatic system which has several disadvantages compared to an electric driven unit. In this research, an electric driven unit for an automatic retractable bollard is designed and developed to replace the conventional hydraulic and pneumatic driven type. For the reliability test of the developed electric driven unit, a field test has been successfully done. A case study was conducted to develop a defensive retractive bollard which the target performance is 9sec. and 7sec. on its raising and descending operation speed respectively with 750mm in stroke. The required time limit was fully satisfied as the time measured from the experiment were 7.5sec and 5.5sec for each operation. The developed unit also passed 364,000 cycles of operation without any serious malfunctions at the load test proving its reliability. The design theory and process of an electric driven unit of the automatic retractable bollard presented in this article is believed to be very useful contribution and design tool in advancing the physical security industry.

In general, the pretensioned PSC members are manufactured at the factory and are transported to the site. Due to road conditions, their sizes are limited. Therefore, until now pretensioning method is only applied to small PSC members. In order to produce large scale PSC members using pretensioning method, they shall be made on site. In this study, a portable prestressing device to produce pretensioning PSC girders on site has been developed. The portable prestressing device should be safe and stable about jacking force. In this paper, the portable prestressing device to produce 10m-span pretensioning PSC girders was made. The static loading test was performed to analyze the resisting mechanism of each component of that device. The jacking force was introduced by stretching and anchoring the tendons at its both ends. In the static loading test, the structural characteristics of the developed device are investigated.

It is necessary to develop a mobile water production system in order to provide stable water supply in case of disasters such as floods or earthquakes. In this study, we developed a modular mobile water production system capable of producing water for various uses such as domestic water and drinking water while improving applicability in various raw water sources. The water production system consists of three stages of filtration (sand filtration - activated carbon filtration - pressure filtration) to produce domestic water and an additional reverse osmosis process to produce drinking water. In laboratory and field experiments, the domestic water production system showed excellent treatment efficiency for particulate matter, but showed limitations in the treatment of dissolved substances such as dissolved organic matter. In addition, ultraviolet irradiation was considered as additional disinfection step, because it does not form precipitates of manganese oxides after disinfection. Reverse osmosis process was added to increase the removal efficiency of dissolved substances and the treated water satisfied drinking water quality standards. Fluorescence analysis of dissolved organic matter showed that the fulvic acid-like substances in raw water was successfully removed in the reverse osmosis process. The mobile water production system developed in this study is expected to be used not only in water supply in case of disaster, but also widely used in islands and rural area.