• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.335-340
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• 2016

Soil organic carbon plays an important role on soil physico-chemical properties and crop yields in paddy soil. However, there is little information on the soil organic carbon under different forage cultivation during winter season in rice paddy. In this study, we investigated the soil organic carbon and physico-chemical properties in 87 fields of paddy soil cultivated with Barley, rye, and Italian ryegrass (IRG) as animal feedstock during winter season. Organic carbon was 12.9, 14.3, and $16.9g\;C\;kg^{-1}$ in soil with barley, rye, and IRG cultivation, respectively. Among rice-forage cultivation systems, the rice+IRG cropping system was 19.5% higher than in the mono-rice cultivation. Bulk density ranged from 1.17 to $1.28g\;cm^{-3}$ irrespective of cropping systems, and had strongly negative correlation with the soil organic carbon in the rice+IRG cropping system. Carbon storage in rice+IRG cropping systems was average $29.6Mg\;ha^{-1}$ at 15 cm of soil depth, which was 20.4 and 10.3% higher than those of barley and rye cultivation. Increasing carbon storage in paddy soil contributed to the fertility for following rice cultivation. This results indicated that IRG cultivation during winter season could be an alternative and promising way to enhance soil organic carbon content and fertility of paddy soil.

• Journal of the Korea Society of Computer and Information
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• v.15 no.10
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• pp.157-164
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• 2010

Recently, the Radio Frequency Identification(RFID) system has been growing with many promising features in technology and applications fields. Especially, a lot of efforts for the application of RFID system in the field of logistics management have been conducted. In addition, in logistics section of steel industry a remarkable efficiency can be attained by application of the RFID system. However, in the RFID system applied for the steel industry, lots of problems were found to be solved in recognition of the tags and antennas. This paper presents the feasibility of deploying RFID in the steel industry as a tool for reduction of the production cost. An application of the steel industry to RFID-based tracking management system was proposed. The results of this paper showed that the recognition rate of material input and output was found 100 percent and secured 99 percent of detection rate in the location. In conclusion, the proposed RFID-based tracking management system was approved superior to the existing system in terms of productivity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.287-289
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• 2015

Internet of Things(IoT) is promising futuristic technology and the relevant market is expected to grow explosively. So, many company develop the product or service that is applied IoT in various fields. The objective of this paper is design and development of collaboration system for enterprise based on beacon to improve efficiency in office environment. We construct Indoor Positioning System(IPS) that using by beacon and mobile device and then develop the related service that utilize IPS data. Thus, we expect that this study contribute to improving productivity of domestic company, is used widely to develop new IoT service that applying various sensors such as beacon, temperature, humidity and so on.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.920-930
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• 1999

Many researches on the multi-level QAM(Quadrature Amplitude Modulation) which is known to be a promising digital data transmission method for efficient use of channel bandwidth have been carried on, and their applications to various real fields are now being in progress. However, in the band-limited communication systems, each transmitted symbols is distorted by the ISI(Intersymbol Interference) and the phase error. Therefore, an equalizer and a carrier recovery must be taken into considerations to attenuate the effects of these distortions in the receiver. This paper presents an effective receiver structures that is applicable to the multi-level QAM. The proposed receiver system is consisted of an equalizer with Godard’s blind algorithm and a carrier recovery circuit. The phase error is estimated with a $\theta$-matching algorithm and is used in the carrier recovery to recover the correct phase. The simulation results are included to evaluate performance of the proposed receiver system for the various channel models.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.171-175
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• 2015

In this paper, because of global environmental problems such as energy shortage and abnormal climate, green energy development and energy saving technology development is being magnified. Heat insulation, the most basic and traditional energy saving method, is highly expected. Especially, simple and advanced heat insulation technique based on Nano material is promising future technology. The railway system also requires heat insulation. Especially, traditional heat insulator such as glass wool has been adopted frequently to rolling stock. The heat insulator is also adopted in general railway service buildings. Take account of cost-effective heat blocking performance, the heat insulator shall be adopted in diverse fields such as electric power, railroad, signal and communication. The only and direct solution for this problem is installing heat insulator with outstanding endurance, corrosion resistance and heat resistance to block outer heat Upgrading heat specification of equipment can be a solution, but since price and maintenance cost rise severely, this plan might be incongruous. In this research, energy saving effect of ultrathin heat insulator film was demonstrated by installing the film on roof of electrical room.

• Korean Journal of Biological Psychiatry
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• v.13 no.2
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• pp.82-94
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• 2006

Objectives : In order to explore effects of board-game therapy for cognitive rehabilitation in patients with schizophrenia, we investigated the change of executive cognitive function over a 2-month period of board-game therapy in patients with schizophrenia. Methods : Two groups of chronic schizophrenic inpatients were participated in this study. One group(n=21) were treated with board-game therapy for 2 months and the other control group(n=19) were not treated. For the evaluation of the executive cognitive function, a Wisconsin Card Sorting Test(WCST) was administered before and after the introduction of the board-game therapy. PANSS score change was also evaluated. Result : At the beginning of this study, there was no significant difference in performance of cognitive function tests, demographical data or clinical severity between both patient groups. After 2 months of treatment with the board-game therapy, the board-game therapy group showed significant improvements of executive cognitive function without any significant change of their schizophrenic symptoms. On the contrary, there was no change in control group. Conclusion : This study showed that a board-game therapy is effective for the enhancement of executive cognitive function in patients with chronic schizophrenia. A board-game therapy could be introduced with ease into psychiatric fields, such as inpatients' or outpatients' clinic wards and day hospital. Our result indicates that the board-game therapy is a promising tool for the enhancement of cognitive function, especially executive cognitive function and helpful for cognitive rehabilitation for schizophrenic patients.

• Composites Research
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• v.28 no.3
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• pp.75-80
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• 2015

Poly(vinylidene fluoride-trifluoroethylene; P(VDF-TrFE)) is one of the most promising electroactive polymers with numerous application potentials in many fields of industry. Because of its good electro-mechanical properties P(VDF-TrFE) has been used for a number of sensors and actuators and also can be used for monitoring composite structure behaviors as a sensor. Three different ways (Electrical poling, annealing-cooling, and pressing) to enhance ${\beta}$-phase of P(VDF-TrFE) film were carried out. A microscopic analysis was conducted using X-ray diffraction to investigate the effect of such treatments on piezoelectric properties of P(VDF-TrFE) film. From the results, poling, annealing-cooling, and pressing were all effective to enhance ${\beta}$ crystallinity of P(VDF-TrFE) film and the maximum increase rate was 62.80% from 45.29% of the control group.

• Clean Technology
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• v.9 no.1
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• pp.9-21
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• 2003

CFC-113 and 1,1,1-TCE which are ozone destruction substances are not used any more in the advanced countries because of Montreal protocol. MC and TCE are now used restrictively at small part of industrial fields in most of countries since they are known to be hazardous or carcinogenic materials. Thus, it is indispensible that the alternative cleaning agents which are environmental-friendly and safe, and show good cleaning ability should be developed or utilized for replacement of the halogenated cleaning agents. Aqueous cleaning agents are evaluated to be promising alternative ones among various alternatives in environmental and economical view point. This study has been carried out as a part of development program of aqueous cleaning agent. First of all, several types of surfactants which are the most important component in aqueous cleaning agents were chosen, and the physical properties, foaming ability, cleaning ability and oil-water separation efficiency of their aqueous solutions were measured and compared for selection of proper type of surfactant in aqueous cleaning agents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.147-150
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• 2020

Relatively pure YBCO was first synthesized by heating a mixture of metal carbonates at temperatures between 1,000 and 1,300 K, resulting in the reaction: 4BaCO₃+Y₂(CO₃)₃+6CuCO₃+(1/2_-x)O₂ → 2YBa₂Cu₃O_7-x+1/3CO₂. Modern syntheses of YBCO use the corresponding oxides and nitrates. The superconducting properties of YBa₂Cu₃O_7-x are sensitive to the value of x, i.e., its oxygen content. Only those materials with 0≤x≤0.65 are superconducting below Tc, and when x ~ 0.07, the material superconducts at the highest temperature, i.e., 95 K, or in the highest magnetic fields, i.e., 120 T and 250 T when B is perpendicular and parallel to the CuO₂ planes, respectively. In addition to being sensitive to the stoichiometry of oxygen, the properties of YBCO are influenced by the crystallization methods applied. YBCO is a crystalline material, and the best superconductive properties are obtained when crystal grain boundaries are aligned by careful control of annealing and quenching temperature rates. However, these alternative methods still require careful sintering to produce a quality product. New possibilities have arisen since the discovery of trifluoroacetic acid, a source of fluorine that prevents the formation of undesired barium carbonate (BaCO₃). This route lowers the temperature necessary to obtain the correct phase at around 700℃. This, together with the lack of dependence on vacuum, makes this method a very promising way to achieve a scalable YBCO bulk.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.105-105
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• 2011

ZnO is a promising material since it could be applied to many fields such as solar cells, laser diodes, thin films transistors and gas sensors. ZnO has a wide and direct band gap for about 3.37 eV at room temperature and a high exciton binding energy of 60 meV. In particular, ZnO features high sensitivity to toxic and combustible gas such as CO, NOX, so on. The development of gas sensors to monitor the toxic and combustible gases is imperative due to the concerns for enviromental pollution and the safety requirements for the industry. In this study, we investigated the effect of substrate temperature and post-annealing on structural and electrical properties of ZnO thin films. ZnO thin films were deposited by pulsed laser deposition (PLD) at various temperatures at from room temperature to $600^{\circ}C$. After that, post-annealing were performed at $600^{\circ}C$. To inspect the structural properties of the deposited ZnO thin films, X-ray diffraction (XRD) was carried out. For gas sensors, the morphology of the films is dominant factor since it is deeply related with the film surface area. Therefore, the atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM) were used to observe the surface of the ZnO thin films. Furthermore, we analyzed the electrical properties by using a Hall measurement system.