• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.3
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• pp.551-569
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• 2024

With the rapid development of electric vehicles (EVs) industry, EV charging service becomes more and more important. Especially, in the case of suddenly drop of air temperature or open holidays that large-scale EVs seeking for charging devices (CDs) in a short time. In such scenario, inefficient EV charging scheduling algorithm might lead to a bad service quality, for example, long queueing times for EVs and unreasonable idling time for charging devices. To deal with this issue, this paper propose a Deep-Q-Network (DQN) based two-stage scheduling method for the large-scale EVs charging service. Fine-grained states with two delicate neural networks are proposed to optimize the sequencing of EVs and charging station (CS) arrangement. Two efficient algorithms are presented to obtain the optimal EVs charging scheduling scheme for large-scale EVs charging demand. Three case studies show the superiority of our proposal, in terms of a high service quality (minimized average queuing time of EVs and maximized charging performance at both EV and CS sides) and achieve greater scheduling efficiency. The code and data are available at THE CODE AND DATA.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.88-96
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• 1972

1. The present paper deals with the contents of heavy metals such as mercury, cadmium, lead and copper in 17 species of edible seaweeds collected from Jumunjin, Pohang, Pusan, Chungmu, Yeosu and Wando areas. 2. The concentration of mercury in the air-dried seaweeds ranged from 0.02 to 0.52 ppm, as shown by the following species: 0.36ppm (0.09-0.50) in Enteromorpha spp., 0.25 ppm (0.14-0.31) in Undaria sp., 0.19 ppm (0.02-0.52) in Porphyra spp., and 0.10ppm (0.02-0.24) in Laminaria spp. in that order. If these concentrations are converted to the wet bases, they will be about 1/4 to 1/5 of the present levels. In general, the samples collected from the east coast showed relatively lower levels than those from the south coast. The mercury concentrations found in the Korean seaweeds are lower than the permissible levels reported. 3. The concentration of cadmium in the air-dried seaweeds ranged from 0.02 to 1.48 ppm, and the levels in the different species showed in the following order: 0.97 ppm (0.41-1.18) in Hizikia sp., 0.33 ppm (0.03-0.63) Undaria sp., and 0.32 ppm (0.04-0.67) in Porphyra spp. The concentration of cadmium in the samples on the wet bases become 1/4 to 1/5 of the present level. The laver Porphyra spp. collected from the east coast showed relatively lower levels than those of the cultured species along the south coast. All of the concentrations are still below than the permissible levels. 4. In general, lead concentration is 0.20-1.31 ppm which is lower than the permissible level. The concentration becomes about 0.05-0.3 ppm on the wet base. 5. Copper concentration ranged from 0.90-17.0 ppn on the dry base which is about 0.2-4.0 ppm on the wet base. It is interesting to note that the samples collected from Busan region showed relatively higher levels than those sampled from other regions.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2731-2736
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• 2013

We report a new tetrameric supramolecular Cu(II) complex ($Cu_4L_4$ = tetrakis(N,N'-bis(salicylidene)-2,2'-ethylenedianiline)Copper(II)) with a Schiff-base ligand ($H_2L$ = N,N'-bis (salicylaldimine)-1,2-ethylenediamine) containing two N,O-bidentate chelate groups. Though the copper sites of $Cu_4L_4$ are non-coupled, the complex exhibits a unsually high catecholase-like activity ($k_{cat}=935h^{-1}$) when the $Cu_4L_4$ solution is treated with 3,5-di-tert-butylcatechol (3,5-DTBC) at basic condition in the presence of air. Combined information obtained from UV-VIS and EPR measurements could lead the suggestion of the reaction pathway in which the substrate may bind to Cu(II) ions by anti-anti didentate bridging mode.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.347.2-347.2
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• 2016

Recently, in order to improve the performance of the colloidal quantum dot solar cells (CQDSCs), various efforts such as the modification of the cell architecture and surface treatment for quantum dot (QD) passivation have been made. Especially, the incorporation of halides into the QD matrix was reported to improve the performances significantly via passivating QD trap states that lower the life-time of the minority-carrier. In this work, we fabricated a lead sulfide (PbS) QD bilayer treated with different ligands and utilized it as a photoactive layer of the CQDSCs. The bottom and top PbS layer was treated using metal iodide ($MI_x$ and butanedithiol (BuDT), respectively. All the depositions and ligand treatments were carried out in air using layer-by-layer spin-coating process. The fabrication of the active layers as well as the n-type zinc oxide (ZnO) layer was successfully carried out on the bendable indium-tin-oxide (ITO)-coated polyethylene terephthalate (PET) substrate, which implies that this technique can be applied to the fabrication of flexible and/or wearable solar cells. The power conversion efficiency (PCE) of the CQDSCs with the architecture of $PET/ITO/ZnO/PbS-MI_x/PbS-BuDT/MoO_x/Ag$ reached 4.2 %, which is significantly larger than that of the cells with single QD (PbS-BuDT) layer.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.205-223
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• 2018

During launch a spacecraft is subjected to a variety of dynamical loads transmitted through the launcher to spacecraft interface or air-born transmission excitations in the acoustic pressure field inside the fairing. As a result, spacecraft are tested on ground to ensure and demonstrate the global integrity of the structure against these loads, to screen the flight hardware for quality of workmanship and to validate mathematical models. This paper addresses the numerical modelling and simulation of the low frequency sine and random vibration tests performed on electrodynamic shaker facilities to comprise the mechanical-borne transmission loads through the launcher to spacecraft interface. Consequently, the paper reviews techniques and methodologies to derive a reliable and representative coupled virtual vibration testing simulation environment based on experimental data. These technologies are explored with the main objectives to ensure a stable, reliable and accurate control while testing. As a result, the use of the derived simulation models in combination with the added value of improved control and signal processing algorithms can lead to a safer and smoother vibration test control of the entire environmental test campaign.

• Design & Manufacturing
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• v.8 no.2
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• pp.18-22
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• 2014

Two shot molding is one of the injection method which uses two materials or two color materials simultaneously in one mold. Two shot molding is good rate of productivity and economical because of no extra-progress necessary. The cowl grille is located in the bottom of wind shield glass and rolls as a passage of air inlet to inside of vehicle. It consists of body and seal. Firstly, the body is injected with PP. Next seal is extruded with EPDM and engineered and then assembled with body. These procedures lead high cost of production and the quality of part has problems. Therefore, it has effects on saving production cost and being a solution of the quality problems with the development of two shot molding cowl grille. It is guaranteed that two shot molding will be widely used in the vehicle parts industry afterwards.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.603-607
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• 2009

About a Structure is performance external insulation is fundamantal performance for enrgy-saving. these day, most of residential structures have constructed by internal insulation method structure. The method structure internal insulation have construction and economical efficiency, but on the other hand, be generated heat loss by heat bridge especially, be generated loss heat-energy logical consequence in structure ondol. The external insulation structure method has a mert able to minimum to loss heat about heat-bridge. But the external insulation technique is unsatisfactory statues within the know-how and method of construction and materials compared with developed countries. The recently, the requirement of market related to the external insulation technique is resulted by the energy efficiency system, but it can lead to the lack of alternative technique In study on the korea type passive house building design for insulation block method of wall system has to experimental characteristic heat-energy of practice building. In result field-experimental, the heat-bridge appeared to characteristic spent heat-energy of blow 2L class and have a suffience performance it.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.54-59
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• 2008

The poor maintenance and management of HVAC systems finally lead to the shortening of the life expectancy and result in the increase of operating costs and energy consumptions due to low efficiencies. Also, it is essential to try to develop ways to adequately maintain and to use the building facilities efficiently in order to preserve earth environment and the limited resource. In this study, an analysis on the maintenance and management cost for HVAC systems was carried out with the capacity of equipment. Besides, the LCC(Life Cycle Cost) based analysis was carried out to verify the effect of the doing maintenance and management. As the results, the case of the good maintenance and management is able to save LCC to 11 % than the case of the poor method.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.222-227
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• 2004

Flotation processes involve the use of very small bubbles (micro-bubbles) to separate particles from water. The process has become a good alternative to sedimentation, especially where the particles are small or of low density. Although the flotation process commences with a collision between particles and bubbles, most research has been focused only on the characteristics of the particles. In this paper, recent theoretical and experimental research on the characteristics of bubbles is summarized. The effect on the collision efficiency of the size and charge of bubbles is calculated through trajectory analysis. The size and charge of bubbles are measured under different conditions and the ramifications of the results are discussed. The results may lead to a better understanding and optimization of the existing process. In particular, we discuss an idea that a new advanced flotation process might be possible by the modification of the characteristics of the bubble alone or of both bubble and particle.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.360-367
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• 2016

A windowless spallation target can provide a neutron source and maintain neutron chain reaction for a subcritical reactor, and is a key component of China's nuclear waste transmutation of coupling accelerator and subcritical reactor. The main issue of the windowless target design is to form a stable and controllable free surface that can ensure that energy spectrum distribution is acquired for the neutron physical design when the high energy proton beam beats the lead-bismuth eutectic in the spallation target area. In this study, morphology and flow characteristics of the free surface of the windowless target were analyzed through the volume of fluid model using computational fluid dynamics simulation, and the results show that the outlet cross section size of the target is the key to form a stable and controllable free surface, as well as the outlet with an arc transition. The optimization parameter of the target design, in which the radius of outlet cross section is $60{\pm}1mm$, is verified to form a stable and controllable free surface and to reduce the formation of air bubbles. This work can function as a reference for carrying out engineering design of windowless target and for verification experiments.