• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.6
• /
• pp.721-733
• /
• 2023

As the frequency of extreme rainfall events increase due to climate change, climate change adaptation measures have been proposed by the central and local governments. In order to reduce flood damage in urban areas, various flood response policies, such as low impact development techniques and enhancement of the capacity of rainwater drainage networks, have been proposed. When these policies are established, regional characteristics and policy-effectiveness from the cost-benefit perspective must be considered for the flood mitigation measures. In this study, capacity enhancement of rainwater pipe networks and low impact development techniques including green roof and permeable pavement techniques are selected. And the flood reduction effect of the target watershed, Gwanak campus of Seoul National University, was analyzed using SWMM model which is an urban runoff simulation model. In addition, along with the quantified urban flooding reduction outputs, construction and operation costs for various policy scenarios were calculated so that cost-benefit analyses were conducted to analyze the effectiveness of the applied policy scenarios. As a result of cost-benefit analysis, a policy that adopts both permeable pavement and rainwater pipe expansion was selected as the best cost-effective scenario for flood mitigation. The research methodology, proposed in this study, is expected to be utilized for decision-making in the planning stage for flood mitigation measures for each region.

• Journal of the Korea Computer Industry Society
• /
• v.2 no.4
• /
• pp.565-572
• /
• 2001

At the most recent years, laser medical instruments, laser applications and laser nuclear fusion need strong visible light and ultraviolet rays. Nonlinear optical devices, such as harmonic generators and parametric oscillators, provide a means of extending the frequency range of available laser sources. Frequency conversion is a useful technique for extending the utility of high-power lasers. It utilizes the nonlinear optical response of an optical medium in intense radiation fields to generate new frequencies. These progresses have been used to generate high-power radiation in all spectral regions, from the ultraviolet to the far infrared. Optical parametric oscillators and amplifiers generate two waves of lower frequency They are capable of generating a range of wavelengths from a single frequency source, in some cases spanning the entire visible and near infrared regions. Consequently, in order to obtain the green light, the pulsed Nd:YAG laser using multiple-mesh PFN(Pulsed Forming Network) method with Nonlinear optical device was adopted. We compared the current pulseshapes with the laser output energy, and conversion efficiency.

• Journal of Korean Society of Transportation
• /
• v.30 no.4
• /
• pp.85-94
• /
• 2012

Modern freight transport pursues not only the reduction of logistic costs but also aims at green logistics and efficient shipments. In order to accomplish these goals, various policies regarding the multimodal shipment and stopover to logistic facilities have widely been made. Such situation requires changes in existing methods for analyzing freight demand. However, the reality is that a reliable freight demand forecast is limited, since in the transport research field there is no robust freight demand model that can accommodate transshipments at logistic facilities. This study suggested a novel method to analyze freight demand, which can consider transshipments in multi-modal networks. Also, the applicability of this method was discussed through an example test.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.11
• /
• pp.6932-6942
• /
• 2014

The expressway is a key area of road networks for national industry, economics and social development. In addition, the number of lines are increasing continuously. Recently, road management policy have shown a paradigm shift to safe road, low-carbon and green etc. Nevertheless, the road condition has deteriorated dramatically by fatigue cracking, thermal cracking and weather impact. On the other hand, the budgets for highway maintenance have shrunk dramatically. In this study, an effective pavement management and maintenance process was developed to extend the pavement serviceability and pavement life to overcome the rack of budgets.

• Korean Chemical Engineering Research
• /
• v.56 no.3
• /
• pp.404-409
• /
• 2018

The integration of organic and inorganic building blocks into hierarchical porous architectures makes potentially desirable catalytic material in many catalytic applications due to their combination of dissimilar components and well-constructed reactant transport path. In this study, we prepared the hierarchical porous $Co_3O_4@graphene$ 3D gel by hydrothermal method to achieve high catalytic performance in PET glycolysis reaction. Obtained $Co_3O_4@graphene$ 3D gel consisted of interconnected networks of $Co_3O_4$ and graphene sheets, providing large number of accessible active sites for efficient catalytic reaction. These structural merits from synergistic effect of $Co_3O_4$ and graphene gave a high performance in the PET degradation reaction giving high conversion yield of BHET, fast degradation rate of PET, and remarkable stability.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.6
• /
• pp.229-235
• /
• 2013

This paper proposed the method to reduce and manage the amount of using power by using the Self-Learning of inference engine that evolves through learning increasingly smart ways for each spaces with in the Space-Based Energy Management System (SEMS, Space-based Energy Management System) that is defined as smallest unit space with constant size and similar characteristics by using the collectible Big Data from the various information networks and the informations of various sensors from the existing Energy Management System(EMS), mostly including such as the Energy Management Systems for the Factory (FEMS, Factory Energy Management System), the Energy Management Systems for Buildings (BEMS, Building Energy Management System), and Energy Management Systems for Residential (HEMS, Home Energy Management System), that is monitoring and controlling the power of systems through various sensors and administrators by measuring the temperature and illumination.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.18 no.1
• /
• pp.91-102
• /
• 2015

In connection with biodiversity that has recently become the topic, competition to secure biological genetic resources is being heightened all over the world. Korea also has a variety of efforts to secure and preserve plant genetic resources, and has recognized the importance of the function and role of arboretums. Arboretums in Korea, however, have the problems in terms of quality due to the rapid increase. One of the problems is shortages in experts who are essential for the proper functioning of arboretums. To solve the problem, the State introduced Gardener Training Program certification system and started to train gardeners. However, gardeners who have actually employed at arboretums are less than 20% and thus the problem of shortages in experts still exists. In this context, this study examined 44 registered arboretums in Korea to find out the current situation of experts; analyzed arboretum experts and the program certification system in view of relevant laws; and investigated the current situation of training programs being operated in three Gardener Training Program certification organizations. Finally, this study conducted a survey of 68 gardeners who completed the training program at Chollipo Arboretum and tried to suggest a plan for securing experts from the gardener training programs. The plan for utilizing the trained gardeners as experts in arboretums is as follows: First, legal standards for the employment of experts in arboretums should be strengthened. Second, it is necessary to evaluate training programs, in order to raise the reliability of arboretum experts' expertise. Third, official validity that can be honored in all arboretums should be granted to a certificate of program completion. Finally, networks of gardeners who completed the programs should be formed through follow-up management of them.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37B no.12
• /
• pp.1113-1118
• /
• 2012

Smart grid and intelligent transportation system draw significant interest since they are considered as one of the green technologies. These systems require a large number of sensors, actuators, and controllers. Also, machine-to-machine (M2M) communications is important because of the automatic control. The LTE-Advanced networks is preparing a set of functions that facilitate the M2M communications, and particularly the development of an efficient call admission control mechanism is critical. A method that groups MTC devices according to QoS constraints and determines the admission depending on the QoS satisfaction is limitedly applied only if the data transmission period and the maximum delay are identical. This paper proposed a call admission control that is free from such limitation and also optimizes the admission process under the certain condition of the transmission period and maximum delay. The theorems regarding the proposed method are presented with the proofs. The simulations confirms its validity and shows it is better in call admission probability than existing works.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.4
• /
• pp.1877-1882
• /
• 2013

Smart Utility Network (SUN) is not only a core technology of intelligent green home networks but also a future technology which can be applicable to various areas instead of ZigBee. SUN should be compliment with IEEE 802.15.4g standard and can provide high link margin and stable communication data-rate for poor communication surrounding. This paper describes how to design the system simulation environment for the SUN RF transceiver, and also reports the required block-level specification for each circuit and various implementation impairments. Finally, the measured performances of the fabricated RF transceiver, which has utilized the system simulation results, completely satisfies the IEEE 802.15.4g SUN PHY standard.

• Journal of Adhesion and Interface
• /
• v.16 no.1
• /
• pp.15-21
• /
• 2015

In this study, rheological properties and flow dynamics in roll coating process of basecoat paints have been investigated for automotive precoated metal (PCM) sheet applications. Various rheological properties for basecoats with three colors (black, blue, and silver), such as shear viscosity data at room temperature and elastic/viscous moduli under thermal curing condition, have been measured using a rotational rheometer. It is found that the relative portion of function groups inside basecoats and their viscosity level have greatly affected the formation of crosslinked networks by thermal curing. Also, operability coating windows for basecoats have been established in three-roll coating process system by observing their flow instabilities such as ribbing and cascade. It is confirmed that rheological approaches applied in this study have been usefully applied to develop environmentally-friendly PCM coating technology and optimally control the coating operations for non-Newtonian PCM paints.