• Journal of IKEEE
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• v.24 no.4
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• pp.1122-1128
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• 2020

Bandwidth Extension refers to restoring and expanding a narrow band signal(NB) that is damaged or damaged in the encoding and decoding process due to the lack of channel capacity or the characteristics of the codec installed in the mobile communication device. It means converting to a wideband signal(WB). Bandwidth extension research mainly focuses on voice signals and converts high bands into frequency domains, such as SBR (Spectral Band Replication) and IGF (Intelligent Gap Filling), and restores disappeared or damaged high bands based on complex feature extraction processes. In this paper, we propose a model that outputs an bandwidth extended signal based on an autoencoder among deep learning models, using the residual connection of one-dimensional convolutional neural networks (CNN), the bandwidth is extended by inputting a time domain signal of a certain length without complicated pre-processing. In addition, it was confirmed that the damaged high band can be restored even by training on a dataset containing various types of sound sources including music that is not limited to the speech.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.341-347
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• 2023

The subway is one of the most common and important means of transportation in modern society. In order to use the subway safely, tracks are necessary, but trains are prone to derailment and collisions. In order for the train to run safely on the track, the fishplate that connects the line connection is used. The damaged railway was a fishplate for connecting subway lines used for 11 years, and damage analysis and countermeasures were presented. Beach marks were observed on both fracture surfaces, and striations appeared at the range of crack propagation. The damaged part is Cr carbide, which has a higher hardness than the base metal, and is judged to be embrittled and destroyed by fatigue. The SM50C fishplate was subjected to a cyclic stress of about 59% of the upper limit of tensile-compression fatigue limit, but inclusions were the cause of failure. In order to prevent fatigue failure of the SM50C steel fishplate, the occurrence of inclusions should be minimized and processed to have a homogeneous structure when manufacturing the fishplate. In addition, compressive residual stress is given through surface modification such as peening to control crack generation. It is necessary to minimize the change in shape that can become a stress concentration part along with accurate fastening of the bolt, and to design the stress distribution to be as uniform as possible.

• Journal of Digital Policy
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• v.3 no.1
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• pp.27-32
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• 2024

In this paper, proposes a super resolution method that enhances the quality of results by refining texture features, contrasting each, and utilizing the results as weights. For the improvement of quality, a precise and clear restoration result in details such as boundary areas is crucial in super resolution, along with minimizing unnecessary artifacts like noise. The proposed method constructs a residual block structure with multiple paths and skip-connections for feature estimation in conventional Convolutional Neural Network (CNN)-based super resolution methods to enhance quality. Additional learning is performed for sharpened and blurred image results for further texture analysis. By contrasting each super resolution result and allocating weights through this process, the proposed method achieves improved quality in detailed and smoothed areas of the image. The experimental results of the proposed method, evaluated using the PSNR and SSIM values as quality metrics, show higher results compared to existing algorithms, confirming the enhancement in quality.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.672-679
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• 2001

Background: Surgical correction of partial anomalous pulmonary venous connection to the superior vena cava has been associated with postoperative venous obstruction and sinus node dysfunction. In this paper we describe our current approach and its short-term results. Material and Method: Between April 1999 and January 2000, 5 consecutive patients, ranging from 2 months to 66 years old, underwent corrective operation for partial anomalous pulmonary venous connection to the superior vena cava at Sejong General Hospital and Daegu Catholic University Medical Center. Surgical correction involved diversion of the pulmonary venous drainage to the left atrium using a right atrial flap(2 patients) or prosthetic patch(3 patients) with division of the superior vena cava superior to the restore site of the pulmonary veins and reimplantation on the right atrial appendage to restore systemic venous drainage. Result: All patients were discharged between postoperative day 9 and 15 without complications. One Russian boy returned to his country, therefore, he was lost to follow-up after discharge. Remaining 4 patients were asymptomatic and in normal regular sinus rhythm at a mean follow-up of 17.75$\pm$4.27 months. Follow-up echocardiographic study (range, 12 to 24 months) revealed no incidence of narrowing of the venous pathways or of residual shunt. Conclusion: Our current approach is relatively simple and reproducible in achieving unobstructive pulmonay venous and SVC pathways. By avoiding incision across the cavoatrial junction, surgical injury to the sinus node and its artery may be minimized. The presented surgical technique can be safely and effectively applied to the selected patients.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.6 no.4
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• pp.153-171
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• 2011

The welfare system and the direction of the welfare policy have been unable to escape greatly from the frame of the past against the facts that the external environments of the national economy of the world including Korea have been changing in quick and rapid speed. Such results have caused the issues related with the welfare, economy and society ended in the ideological collision in connection with the goals of the policy, the right agreement between the policies lacked, and the intervention and conflict between the interest group concerning the policy continued. Social policy of Korea in the past had the level of complementing the parts which could not be solved through the growth. Employment creation had been achieved continuously backed up by the high rate of growth. And the low aging level, the young population structure, and the high rate of childbirth had been the structures that made such achievement possible. New economic, social and welfare environment at home and abroad has been requesting new change in welfare policy. Goal of the economic and social policy is to construct the safe economic and social system. And what has been requested has been the formation of the economic and social policy orienting the welfare nation in form of social investment and welfare expansion. Also the direction in strengthening the welfare system of Korea shall have the balance between the protection and activation strength with the necessity of converting to the prevention welfare from the post welfare. Also the public part, market, the 3rd sector and the share of the role of an individual shall be achieved. And what is needed is the achievement of the transfer from the paradigm of residual welfare to the universal welfare. And such improvements of the welfare system will be able to elevate the possible continuity of the system in long term basis through the improvement of the welfare system.

• Archives of Craniofacial Surgery
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• v.17 no.3
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• pp.128-134
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• 2016

Background: Blowout fracture is one of the most common facial fractures, and patients usually present with accompanying ocular complications. Many studies have looked into the frequency of persistent ocular symptoms, but there is no study on assault patients and related ocular symptoms. We evaluated the incidence of residual ocular symptoms in blowout fractures between assaulted and non-assaulted patients, and sought to identify any connection among the degree of enophthalmos, defect size, and assault-related injury. Methods: A retrospective review was performed for any patient who sustained a unilateral blowout fracture between January 2010 to December 2014. The collected data included information such as age, gender, etiology, and clinical ocular symptoms as examined by an ophthalmologist. This data was analyzed between patients who were injured through physical altercation and patients who were injured through other means. Results: The review identified a total of 182 patients. Out of these, 74 patients (40.7%) have been struck by a fist, whereas 108 patients (59.3%) have sustained non-assault related injuries. The average age was 36.1 years, and there was a male predominance in both groups (70 patients [94.6%] in the assaulted group and 87 patients [80.6%] in the non-assault group). Diplopia and enophthalmos were more frequent in patients with assault history than in non-assaulted patients (p<0.05). Preoperatively, 25 patients (33.8%) with assault history showed diplopia, whereas 20 patients (18.5%) showed diplopia in the non-assaulted group (p<0.05). Preoperative enophthalmos was present in 34 patients (45.9%) with assault history, whereas 31 patients (28.7%) showed enophthalmos in the non-assaulted group (p<0.05). Conclusion: Patients with an assault history due to a fist blow experienced preoperative symptoms more frequently than did patients with non-assault-related trauma history. Preoperative diplopia and enophthalmos occurred at a higher rate for patients who were assaulted. Surgeons should take into account such characteristics in the management of assaulted patients.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.183-197
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• 1990

The purpose of this study was to analyse the magnitude and distribution of stresses using a Photoelastic model from and distal - extension removable partial dentures With four designed indirect retainers. The designs of the indirect retainers were as follows : Design No. 1 : Aker's clasp on 1st bicuspid with no indirect retainer. Design No. 2 : Aker's clasp on 1st bicuspid with indirect retainer on canine. Design No. 3 : Extension of the reciprocal arm of Aker's clasp toward incisal rest on canine. Design No. 4 : Connection with the indirect retainer as in No. 2 and extension of reciprocal arm of Aker' s clasp. A photoelastic model was made of the epoxy resin(PL - 1) and hardner(PLH - 1) and coated with plastic cement -1(PC -1) at the lingual surface of the epoxy model and set with chrome - cobalt partial dentures. A unilateral vertical load of 10kg to the right 1st molar and a vertical load of 10kg to the middle portion of the metal bar crossing both the 1st molars of the right and left, were applied. With the use of specially designed jig, fixture; loading device and the reflective circular polariscope, we obtained the following results : 1. When the unilateral vertical load and the vertical load of the middle portion of the metal bar were applied, design No. 2, 3 and 4 exhibited the higher stress concentration at the root apices and their surrounding tissues of the primary and secondary abutment teeth. 2. When the unilateral vertical load applied to design No. 2,3 and 4 the root apices of the primary and secondary abutment teeth and their surrounding tissues and the nonloaded side of edentulous area exhibited and even stress distribution. 3. When the vertical load was applied, the stress concentration fringe in the primary and secondary abutment teeth was in the order of No. 1,4,2 and 3. 4. No.1 and 4 exhibited the higher distrorted stress concentration at the primary teeth and the edentulous area in the nonloaded side. 5. No.2 design reduced the stresses at the apices of the alveoli of the primary abutment teeth bilaterally as well as on the crest of the residual ridge on the nonloaded side. 6. No. 2 design exhibited the most favorable stress distribution.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.204-209
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• 2015

The effluent limit of nickel from electroplating wastewater has been strengthened from 5 mg/L to 3 mg/L from 2014. However, currently applied treatment process for nickel plating wastewater is unable to meet the effluent limit, most of the treatment concept conducted by treatment plant is dilution with other metal bearing wastewater. This can cause very significant impact to the environment of nickel contamination. With this connection, the feasibility test has been conducted with the use of electrolysis by using sacrificial electrodes. Experiments were conducted in synthetic and electroless nickel plating wastewater. Optimal condition of current density, pH were derived from the synthetic wastewater. It was found that the removal efficiency of nickel exceeded 94% at the operation condition of at pH 9 and the current density of $1{\sim}2mA/cm^2$. At this conditions, the iron sludge was generated very low amount. However, it was unsuccessful to meet the effluent limit by applying these treatment conditions to the real electroplating wastewater. This can be explained due to the matrix effect of other metals and anions contained real electroplating wastewater. From the result of further study, the optimal conditions for the real wastewater treatment were found out to be at pH 9, current density $6{\sim}7mA/cm^2$, for 5 minutes of operating time. At these conditions, 88% removal of nickel was achieved, which results the residual nickel concentration was below 3 mg/L.

• Applied Microscopy
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• v.28 no.4
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• pp.603-613
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• 1998

The present study was designed in order to observe relationship between the endoplasmic reticulum and the Golgi complex during spermiogenesis of the long-fingered bat (Miniopterus schreibersi fuliginosus). The testes were obtained from adult bats and treated with the prolonged osmification or fixed with ferrocyanide reduced osmiun. In the Golgi phase, The Golgi complex shows an oval shape, and was composed of a cortex and a medullar enclosing acrosome. The Golgi vacuoles with electron-dense granules of crescent shape were fused with each other. The smooth endoplasrnic reticulum was scattered in all the area of the cytoplasm. In the cap phase, The Golgi complex was crescent in shape, and faced to a nucleus. Large and small vesicles were fused with each other, and then fused with a acrosomal vacuole. The rough endoplasmic reticulum was close to the large Golgi vacuole. In the acrosome phase, The Golgi complex was moved to behind of the acrosome face. Small vesicles were fused with an acrosome, and cisternae of the trans-face of Golgi complex was connected with an acrosome in the early acrosome phase. The smooth endoplasmic reticulum was distributed in the cytoplasm. The annulate lamellar was originated from a radial body-annulate lammellae complex. In the maturation phase, The Golgi complex with dilated cistrern appeared in the cytoplasm, and also, annulate lamellar was observed in the cytoplasm. The connection of the annulate lamellar with the cistern of radial body suggests that an annulate lamellar seems to be closely related to radial body. The smooth endoplasmic reticulum was scattered in the cytoplasm in the early Golgi phase, but annulate lamellar-radial body complex which might be a residual and disappearing form of the smooth endoplasmic reticulum appeared in the acrosome phase. The Golgi complex steadily remained in the late maturation phase when the endoplasmic reticulum began to disappear from the cytoplasm: the Golgi complex was still occurred after acrosome formation. The observations obtained in the present study, which was characterized by the presence of the Golgi complex in the late maturation phase, suggests that the Golgi complex may play an important role also even after the acrosome formation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.462-466
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• 2010

The purpose of this study is to evaluate the safety of a wire connector fabricated for the effective installation of a lighting fixture including its contact resistance, insulation resistance, withstanding voltage characteristics, etc., and to provide the basis for the analysis and judgment of PL(Product Liability) dispute by presenting a damage pattern due to a general flame and overcurrent. This study applied the Korean Standard (KS) for the incombustibility test of the connector using a general flame and performed an overcurrent characteristics test of the connector using PCITS (Primary Current Injection Test System). The contact resistance of the housing connector was measured using a high resistance meter and the insulation resistance was measured using a multimeter. In addition, a supply voltage of AC 1,500V for testing the withstanding voltage characteristics was applied to both ends of the connector. Measurement was performed on 5 specimens and the measured values were used as a basis for judgment. Since the connector is fabricated in the form of a housing, it can be connected and separated easily and has a structure that allows no foreign material to enter. In addition, since it has a structure that allows wires to be connected only when their polarity is identical, any misconnection that may occur during installation can be prevented. When the incombustibility test was performed by applying a general flame to the connector, it showed outstanding incombustibility characteristics and the blade and blade holder connected to the housing remained firmly secured even after the insulation sheath (PVC) was completely destroyed by fire. In addition, the mechanism of the damaged connecting wire showed a comparatively uniform carbonization pattern and it was found that some residual melted insulation material was attached to both ends. In the accelerated life test (ALT) to which approximately 500% of the rated current was applied, the connector damage proceeded in the order of white smoke generation, wire separation, spark occurrence and carbonization. That is, it could be seen that the connector damaged by overcurrent lost its own metallic color with traces of discoloration and carbonization. The contact resistance of the connector at a normal state was 2.164mV/A on average. The contact resistance measured after the high temperature test was 3.258mV/A. In addition, the insulation resistance after the temperature test was completed was greater than $10G\Omega$ and the withstanding voltage test result showed that no insulation breakdown occurred to all specimens showing stable withstanding voltage and insulation resistance characteristics.