• Journal of Internet Computing and Services
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• 제5권1호
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• pp.15-23
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• 2004

This paper presents distributive web-caching technique on the Head-End-Network (HNET) to solve excessive load of multimedia sever and inefficient use of network resources, The proposed web-caching is not concentration of load for a specific Head-End-Node(HEN), and it has advantage that there is no copy of a specific item on distributive HENs. This technique distributively stores on HENs partial streams of requested videos from clients connected to HENs and the order of store streams follows the order of request of identical video items from HENs. Thus, storing streams on each HEN that requests sevice are different. When a client requests the cached video on some HENs, the HEN that connects him receives streams in the order of store from HENs which stored them and it transmits them to him. These procedures are performed under the control of SA. This technique uses cache replacement algorithm that the combination of LFU, LRU and the last remove for the first stream of videos In order to reduce end-to-end delay.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.69-74
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• 2006

Residual stresses are introduced in aluminum cylinder head during quenching at the end of the T6 heat treatment process. Tensile residual stress resulted from quenching is detrimental to fatigue behavior of a cylinder head when it is overlapped with stresses of engine operation load. Quenching simulation has been performed to assess the distribution of residual stress in the cylinder head. Analysis revealed that in-homogeneous temperature distribution led to high tensile residual stress at the foot of the long intake port, where high stresses of engine operation load are expected. Measurements of residual stress have been followed and compared with the calculated results. Results successfully proved that high tensile residual stress, which was large enough to accelerate fatigue failure of the cylinder head, are formed during quenching process at the end of heat treatment at the same critical position. Effect of quenching parameters on the distribution of residual stress in cylinder head has been investigated by choosing different combination of heat treatment parameters. It was demonstrated that changes of quenching parameters led to more homogeneous temperature distribution during cooling and could reduce tensile residual stress at the critical region of the cylinder head used in this study.

• Korean Journal of Bronchoesophagology
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• 제3권2호
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• pp.287-292
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• 1997

We report 22 cases of well -differentiated thyroid carcinoma infiltrating the upper airway tract. This retrospective study was undertaken to evaluate the prognosis md to determine optimal therapy for thyroid carcinoma adhering to or invading the trachea or larynx from 1984.3 to 1996.12. The treatment was individualized depending on the extent of the cancer. There were 12 cases dissected free by an laryngotracheal shaving, 7 cases removed by an tracheal resection with end to end anastomosis, 3 cases removed by an total laryngectomy. In all of these cases, we performed a total thyroidectomy with an accompanying neck dissection. There were no major complications during the operation. Over the 5-years observation period, 11 patients are alive without a sign of recurrence, 4 Patients are alive with recurrence, 7 died of thyroid carcinoma; 2 of 12 in an laryngotracheal shaving cases, 2 of 7 in an tracheal resection with end to end anastomosis case, 3 of 3 in an total laryngectomy case. The result showed an radical operation for thyroid carcinoma invading the laryngotrachea improves the survival rate, but limits improving the cure rate, and the invasion of the thrchea or larynx must be treated whenever possible by an total resection followed by radioiodine and external beam radiation.

• ETRI Journal
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• 제43권6호
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• pp.1038-1048
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• 2021

We propose an end-to-end neural coreference resolution for the Korean language that uses an attention mechanism to point to the same entity. Because Korean is a head-final language, we focused on a method that uses a pointer network based on the head. The key idea is to consider all nouns in the document as candidates based on the head-final characteristics of the Korean language and learn distributions over the referenced entity positions for each noun. Given the recent success of applications using bidirectional encoder representation from transformer (BERT) in natural language-processing tasks, we employed BERT in the proposed model to create word representations based on contextual information. The experimental results indicated that the proposed model achieved state-of-the-art performance in Korean language coreference resolution.

• Journal of the Korea Safety Management & Science
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• 제25권2호
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• pp.153-158
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• 2023

This research was conducted to reduce the defect rate caused by nozzle clogging of printing heads used in binder jet 3D printers. The binder jet 3D printing technology may adhere to the printing head nozzle by dispersing powder due to mechanical operation such as transferring the printing head and supplying powder, and may cause nozzle clogging by natural curing at the nozzle end depending on the type of binder used. To solve this problem, this study created a cleaning module exclusively for printing heads to check whether the durability of printing heads is improved through analysis of printing results before and after using the cleaning module. To this end, this research used a thermal bubble jet printing head, and the used powder was studied using gypsum powder.

• The Korean Journal of Physiology
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• 제30권2호
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• pp.237-247
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• 1996

This study was carried out to determine the effect of $-6^{\circ}$ head-down bedrest on the cardiovascular and hormonal responses to orthostasis and to evaluate the mechanism of orthostatic intolerance. Ten healthy young men were changed the body position from $-6^{\circ}$ head-down or supine bedrest for 2 hr to $70^{\circ}$ head-up tilt for 20 min. During the bedrest, there were no differences in hemodynamic and hormonal changes between the head-down and the supine positions. However, the tendency of decreased end-diastolic volume and increased cardiac contractility during the later period of 2 hr showed that the cardiovascular adaptation could be accelerated within a relatively short period in the head-down bedrest. During the head-up tilt, presyncopal signs were developed in five subjects of the supine bedrest, and one of the same subjects of the head-down bedrest. In the tolerant subjects, the increase in cardiac contractility and plasma epinephrine level during the bend-up tilt was greater following the head-down bedrest than that following the supine bedrest to compensate for reduced venous return. The intolerant subjects showed the greater decrease in end-diastolic and stroke volume, and the greater increase in heart rate during the head-up tilt than the tolerant subjects. Cardiac contractility and plasma epinephrine level were remarkably increased. However, arterial pressure was not maintained at the level for the appropriate compensation of the reduced venous return. It seems that the tolerance to orthostasis is more effective after the short-term head-down bedrest than after the supine bedrest, and the secretion of epinephrine induces the higher cardiac performance as a compensatory mechanism fur the reduced venous return during the orthostasis following the head-down bedrest than the supine bedrest.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.536-545
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• 2006

In this study the behavior of piles with an extended head is invested experimentally using reduced-scale model tests. Special attention is given to verifying the increase of end bearing capacity of piles with spreading head. Model piles and extended head plates made of steel pipe were used in this study. Bearing capacity of piles is regarded as only end bearing capacity. The study analyzed the tendency of single and group pile of bearing capacity compared with the existing PHC pile, and examined optimum effect of extended head.

• Journal of Convergence for Information Technology
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• 제10권10호
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• pp.47-52
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• 2020

The general flatbed printer system is composed of a PC and a dedicated S/W, which is inconvenient to use. In the end, there is a need for a technology that can easily and conveniently use various types of printing through simplification, smartization, etc. of a flatbed printer system configuration. That is, there is an increasing demand for multi-dimensional printer capable of printing on various types of materials with one printer and capable of printing various types of products. Therefore, in this paper, we developed a flatbed printer system capable of multi-dimensional printing using Head Encoder/Trigger control. To this end, we developed a flatbed printer that connects the internal module of the flatbed printer with an input type detection sensor and controls all operating states by the head encoder and head trigger signals of the printer through separate main controllers. Through this, the development and diffusion of IoT technology will expand the printer control of the smart environment to the developed form throughout the industry. It is expected to contribute to the development of the 3D printing industry in the future.

• Korean Journal of Head & Neck Oncology
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• 제12권1호
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• pp.8-15
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• 1996

When thyroid carcinoma invades the larynx or trachea, the proper treatment is needed because of significant morbidity and mortality due to airway obstruction. Hemoptysis and dyspnea are the result of intraluminal extension of the tumor and call for immediate investigation with endoscopic examination and CT. If the thyroid carcinoma with extracapsular spread invades only outer perichondrium of the tracheal or laryngeal cartilage, the shaving operation would be sufficient, but if the tumor invades the cartilage or if there is intraluminal invasion, it is mandatory to remove partial or total part of some aerodigestive tract structures. We retrospectively analyzed 14 surgical cases of the thyroid cancer with laryngotracheal invasion(12 papillary carcinomas and 2 anaplastic carcinomas) at the Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital. The analysis was focused on clinical manifestation, pathologic findings, types of management and results. Survival result was not adequately analyzed due to some recently operated cases.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.435-439
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• 2002

In the pneumatic system, pneumatic cylinder is wildly used to factory automation. In general, Pneumatic cylinder problems are occured with colliding to stroke end part at which piston collide to end-cap, head cap and tube when piston is loading. This appearances have a short life of cylinder and is due to system destruction. This study examines the dynamic characteristics of pneumatic cushioning cylinder and cushion sleeve design. At head part cushion chamber for the vertical experimental, The decisions of cushioning effect and the results of the experimental research are obtained to the followings: i) The cushioning effects could acqure to the reserch, if the compressible energy is more than kinetic ones. ii) The collision of piston and head cover could acqure to the research, if the kinetic energy is more than compressible iii) If the load increase to the rolling car, the cushion region pressures would increase and the dynamic force.