• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.701-706
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• 2023

The Korean government and industry have presented a roadmap for the commercialization of UAM services and are promoting it in earnest. In order to introduce full-scale UAM services, there are various issues to be solved, such as the development of high-performance aircraft, the design of network bases and corridors, the optimization of operation management, and the establishment of related laws and systems. In this study, in terms of optimizing operation management, we will examine research trends by field, focusing on Korea, and derive research topics that need to be solved in the future. Korean researchers have suggested that research is centered on UAM service usage fees, usage intentions and acceptance models, and vertiport location selection, but operational optimization studies such as service order acceptance, aircraft repositioning, and battery charging and maintenance scheduling are needed in the future.

• Korean Journal of Construction Engineering and Management
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• v.12 no.5
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• pp.71-80
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• 2011

Flying net should be installed on every 3 or 4 construction floor from 8m above ground according to the rule. In the apartment housing construction, flying net installation work has been recognized the most dangerous work among the whole works because a small mistake of labors might make their death accident. Sub-contractors specialized in flying net have been developing various flying net types. However, most works of installing flying net as working with the developed system are performed outside the apartment housing, so that the risk of fall in works of installing supports and unfolding net is still high. Furthermore, as using the previously developed flying net labors might bump into the frame or the wire rope for supporting so that it makes secondary accidents. The objective of this research is to produce the proto-type of anti-collision flying net system based on the result of problem analysis on the installation and detachment process and suggest the improved anti-collision flying net system, which is able to improve safety and field applicability by conducting field experiment and analyzing performance.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.23-32
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• 2017

The joints between precast PSC slabs of the intermediate road slab in double deck tunnel are inevitably generated in the road traffic vehicle traveling direction. Therefore, it is important to make the behavior of parts on the joint in one piece. The imtermediate road slab system of double deck tunnel in great depth proposed in this study will be constructed with precast PSC slab in order to minimize the construction period. And the joint connection between the precast slab has been developed in two methods: the 'Transverse tendon reinforcement method' and 'High strength bolts connection method'. Also, the experiments were performed for the full scale model in order to evaluate the performance of the intermediate road deck slab with two type joints systems, the structural stability was verified through the F.E.M analsysis. The results of static loading test and F.E.M analysis investigated a very stable behavior of intermediate road deck slab in double deck tunnel applying the joint methods developed in this study, in the cracks and deflections to satisfy the design standards of Highway Roads Bridges (2011), it was determined that there is no problem even servicebility.

• Journal of the Korean Professional Engineers Association
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• v.29 no.2
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• pp.15-23
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• 1996

With the ever-increasing importance of high-speed information in society as we move towards the 21 st century, telecommunication laboratories of advanced nations are pressing forward with research and development aimed at implementing its W & P(Visual Intelligent and Personal) services and construction of a new network to support them. In legals to the former, based on a long-term view of technological and market trends, those laboratories are researching and developing services that will make possible an effective progression from the development of services that answer to potential needs towards the full-scale implementation of VI & P services. In regards to the latter, these laboratories are responding in a flexible manner to the increasing diversity and disposal of the communications environment by separating the network into a transmission system and a versatile information control/conversion -ion system and laboratories are working at enhancing the performance of both. Within these board aims, the laboratories are currently focusing our attention in three areas : the technology for a high-speed broadband transmission system featuring optical frequency multiplexing and ATM techniques, network and software technologies for advanced information control and conversion, and technology for constructing a new access network that can provide a comprehensive range of multimedia services. This article describes the laboratories' concept of how VI & P services will develop in the future, and the latest trends in the field of communications. It also describes the ideal configuration of the new network and discusses the important technological aspects of how it is to be constructed. Finally, it presents the results of the laboratories'recent research which include some innovative work, point out the areas requiring future investigation.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.30-35
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• 1996

It is well known that the improved methods of the estimation of the service power margin is necessary to design a optimum ship and to operate economically a ship. Unfortunately, most conventional methods of the predicting of the service power margin are not so accurate that attention should be payed to improve this. From this overview, it is importance with. the effects of waves, as recommended by the 15th and 16th International Towing Tank Conference in 1978 and l981. However the progress of research in this field is very slow mainly since it is taken so long time to take data about hull roughness according to ship ages. For instance, it would be taken 17 or 25 years to measure ideally the data for a ship. Moreover it would be also necessary to take data for many types of ships to lead a general solution. A relationship between roughness and ship age are studied in this paper considering full scale data. A comparison is also made between the effects of hull roughness and of weather at sea for the ship.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.236-244
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• 1999

A feasibility study was performed to examine the agronomic application of treated sewage on paddy rice culture by field experiment. The domestic sewage was treated by the constructed wetland system which was in subsurface flow type and consisted of sand and macrophyte. The effluent of the wetland system was adjusted to maintain the total nitrogen concentration below $25mgL^{-1}$ and used for irrigation water. Four treatments include (1) irrigation of treated sewage after concentration adjusted with conventional fertilization (TWCF), (2) irrigation of treated sewage after concentration adjusted with half of the conventional fertilization (TWHF), (3) irrigation of treated sewage after concentration adjusted without fertilization (TWNF), and (4) irrigation of treated sewage as it was without fertilization (SWNF). These cases were compared to the control case of tap water irrigation with conventional fertilization (Control). Generally, addition of the treated sewage to the irrigation water showed no adverse affect on paddy rice culture, and even improvement was noticed in both growth and yields. TWCF showed the best result and the yields exceed the Control in about 10%. Overall performance of the treatments was TWCF, Control, TWHF, TWNF, and SWNF in decreasing order. From this study, it appears that reuse of treated sewage as a supplemental irrigation water could be feasible and practical alternative for ultimate sewage disposal which often causes water quality problem to the receiving water body. For full scale application, further study is recommended on the specific guidelines of major water quality components and public health.