• International journal of advanced smart convergence
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• v.8 no.4
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• pp.138-146
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• 2019

In this paper, we proposed a soft-switched synchronous buck converter, which can perform charging the battery. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss, resulting in small conduction loss, also. In this reason, the efficiency of the converter can be greatly improved even in high frequency. The size and weight of the converter can be reduced by high frequency operation of the converter. In this paper, we designed a battery charger with a switching frequency of 100 kHz. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery charger had soft switching characteristics. The simulation results for transient response to charge current for the designed converter show that the converter responds to charge current commands quickly within 0.05 ms.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1231-1238
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• 2003

As the demand on multicast services increases to support the terminal mobility in the midst of the development of wireless mobile communication technology, many new methods have been studied. However, previous methods occur delay and packet loss during re-joining to multicast service group when moving mobile node. In this paper, we will propose a scheme that decreases packet loss using regional registration method. Proposed scheme modified signaling message of previous regional-registration and added caching. In case move to same GFA, we can prevent packet loss by keeping registration to FA until perfectly registration ends. Also, In case move to other GFA, we can reduce packet loss by using cache. Therefore, we can receive efficient multicast service.

• Convergence Security Journal
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• v.15 no.3_2
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• pp.71-76
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• 2015

Global companies are building global production network for the demand of the global market. However, the establishment and operation of overseas plants make the unexpected case like theft, low will to produce and salary issue of local workers. Thus in this paper, we propose the raw materials loss prevention model based on IP Camera and RFID Box for raw materials management of overseas plants. This model can prevent the theft or loss of raw materials write inventory up in real-time. This model can be allows us to realize the cost-effective production management because it enables remote inventory management. And this model can prevent brand image danage and profit loss due to reject product.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.80-87
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• 2003

Network reconfiguration in distribution systems is realized by changing the status of sectiona1izing switches, and is usually done for loss minimization or load balancing in the system This parer presents an approach for loss minization in distribution systems using reactive tabu search. Tabu search attempts to determine a better solution in the manner of a greatest-descent algorithm, but it can not give any guarantee for the convergence property. Reactive tabu search can give convergence property by using reaction and escape mechanism. Therefore, it can find global optimal solution regardless of initial system configuration. To demonstrate the validity of the proposed algorithm, numerical calculations are carried out the 32 bus system models.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.10 no.1
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• pp.340-348
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• 1997

The glaucoma, cataract and causing-blindness-diseases have high clinical importance by their severity of the symptoms and possibility of causing visual loss. Glaucoma is caused by an increase in the intraocular pressure, if severe enough, can cause field loss and eventually complete blindness. In cataract, the general clarity of vision is impaired due to a loss of transparency of the chrystalline lens of the eye. The causing-blindness-diseases can be divided to PokMaeng which cause sudden blindness and ChungMaeng, in which visual acuity is losed gradually. In glaucoma, cataract and causing-blindness-diseases, the visual acuity is affected and the patient may complain blurriness, fatigue of eye, visual field loss deficiency or scintillant feeling, vitreous floaters. In this study, 32 patients who have cataract, glaucoma or other causing-blindness-diseases was treated with oriental medicine or acupuncture from July, l996 to May. 1997, and was followed up by their symptoms and visual acuity. 1. In glaucoma patients, intraocular pressure decreased significantry and the symptoms improved positively. 2. In cataract patients, there was no improvement of visual acuity but $40\%$ of patients found their symptoms improved. 3. In causing-blindness-diseases, $57\%$ of patients reported improvement of their symptoms such as blurriness or fatigue of eye. 4. Through oriental medical treatment, the symptoms of glaucoma, cataract and causing-blindness-diseases can be treated effectively. Therefore oriental management seems to be possible to cure glaucoma, cataract and causing-blindness-diseases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.309-310
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• 2005

Generally, the dielectric constant and loss tangent are gotten by resonators. This paper presents analysis of the comparing the dielectric constant and loss tangent from the Ring, T and series gap structures. The T structure can be analyzed easily at wideband characteristic with simple design. the Ring can ignore the radiation loss from the open-ended effect. the Series gap can get more accurate permittivity than a Ring structure. The Used materials were dupont9599 LTCC ceramic and daeju0086 Ag.

• Journal of the Korea Safety Management & Science
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• v.21 no.2
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• pp.15-23
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• 2019

Among service industries of knowledge based economic era, the roles of educational service field are becoming more important and standard of educational service makes a direct effect on economic development and social growth. Therefore, accurate measurement of service quality is the most important assignment and the measurement of the service quality remains difficult assignment. So, this researcher classified quality attributes applying weighted value and found potential satisfaction level(PSL) and potential customer demand improvement index(PCDI) for trainees participating in national manpower business so as to suggest measurement of service quality and easiness of use and then, calculated satisfaction position and opportunity cost by quality factor with Taguchi's loss fraction. And, improvable satisfaction level was measured, opportunity cost by degree of customer dissatisfaction was quantitatively measured, and a model that can indicate with economic factors was suggested. In addition, methodology of measuring quality cost that can be reduced by quality improvement and direction of strategic decision-making for deciding items to be improved preferentially were suggested with qualitative index that can indicate the degree of customers' dissatisfaction by loss.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.2882-2903
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• 2022

Image super-resolution (SR) processing is of great value in the fields of digital image processing, intelligent security, film and television production and so on. This paper proposed a densely connected deep learning network based on cascade architecture, which can be used to solve the problem of super-resolution in the field of image quality enhancement. We proposed a more efficient residual scaling dense block (RSDB) and the multi-channel cascade architecture to realize more efficient feature reuse. Also we proposed a hybrid loss function based on L₁ error and L_∞ error to achieve better L_∞ error performance. The experimental results show that the overall performance of the network is effectively improved on cascade architecture and residual scaling. Compared with the residual dense net (RDN), the PSNR / SSIM of the new method is improved by 2.24% / 1.44% respectively, and the L_∞ performance is improved by 3.64%. It shows that the cascade connection and residual scaling method can effectively realize feature reuse, improving the residual convergence speed and learning efficiency of our network. The L_∞ performance is improved by 11.09% with only a minimal loses of 1.14% / 0.60% on PSNR / SSIM performance after adopting the new loss function. That is to say, the L_∞ performance can be improved greatly on the new loss function with a minor loss of PSNR / SSIM performance, which is of great value in L_∞ error sensitive tasks.

• Tunnel and Underground Space
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• v.27 no.3
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• pp.132-145
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• 2017

Shock loss was not applied for the tunnel ventilation of road tunnel in the past. However, pressure losses due to the shock loss can be significant in network double-deck road tunnel in which combining and separating road structures exist. For the optimum ventilation design of network double-deck road tunnel, this study conducted 3D CFD numerical analysis for the shock loss at the combining and separating flows. The CFD model was made with the real-scale model that was the standard section of double-deck road tunnel. The shock loss coefficient of various combining and separating angles and road width was obtained and compared to the existing design values. As a result of the comparison, the shock loss coefficient of the $30^{\circ}$ separating flow model was higher and that of the two-lane combining flow model was lower. Since the combining and separating angles and road width can be important for the design of shock loss estimation, it is considered that this study can provide the accurate design factors for the calculation of ventilation system capacity. In addition, this study conducted 3D CFD analysis in order to calculate the shock loss coefficient of both combining and separating flows at flared intersection, and the result was compared with the design values of ASHRAE. The model that was not widened at the intersection showed three times higher at the most, and the other model that was widened at the intersection resulted two times higher shock loss coefficients.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.4 s.247
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• pp.343-349
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• 2006

Systematic experiments in $CH_4/Air$ counterflow diffusion flames diluted with He have been undertaken to study the oscillatory instability in which lateral flame size was less than burner nozzle diameter and thus lateral heat loss could be remarkable at low global strain rate. The oscillatory instability arises for Lewis numbers greater than unity and occurs near extinction condition. The oscillation is the direct outcome from the advancing and retreating edge flame. The dynamic behaviors of extinction in this configuration can be classified into three modes; growing, harmonic and decaying oscillation mode near extinction. As the global strain rate decreases, the amplitude of the oscillation becomes larger. This is caused by the increase of lateral heat loss which can be confirmed by the reduction of lateral flame size. Oscillatory edge flame instabilities at low global strain rate are shown to be closely associated with not only Lewis number but also heat loss (radiation and lateral heat loss).