• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.880-884
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• 2014

RT (reverberation time) of outdoor spaces surrounded by multi-storey buildings depends on many designable factors such as the openness, volume and building layouts, etc. This study therefore aims to clarify the influential factors for RT in outdoor spaces surrounded by buildings with complicated topographical conditions. A series of measurements were carried out for 15 outdoor spaces in 6 apartment complexes with different building layouts. An Empirical method considering the openness, averaged ray length and building high is also suggested, to predict RT approximately in the outdoor spaces. The overall results suggest that RT in outdoor spaces of apartment complexes is significantly influenced by source-receiver distance and building layouts.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.141-144
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• 2014

In urban spaces surrounded by buildings, trees could disperse sound energy, which affect sound level distribution and street canyon reverberation. Therefore, this paper examines the amount of scattered sound energy from a tree in open field by means of a reverberation time (RT). Five trees of different species and crown sizes were considered. The influential factors include crown size and shape, foliage condition, and source-receiver distance. The results show that RT is proportionally increased with the increase of tree crown sizes, which is the most determining factor. The maximum RT measured was 0.34 sec at 4000 Hz for the studied trees in leaf. The presence of leaves increased RT at high frequencies, typically by 0.14 sec at 4000 Hz. With increasing source-receiver distance within 40 m, RT was slightly changed.

• The KIPS Transactions:PartD
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• v.10D no.7
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• pp.1145-1148
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• 2003

We show the mixed finite element method which induces solutions that has the same order of errors for both the gradient of the solution and the solution itself. The technique to construct an efficient reusable matrix is suggested. Two families of mixed finite element methods are introduced with an automatic generating technique for matrix with my order of basis. The generated matrix by this technique has more accurate values and is a sparse matrix. This new technique is applied to solve a minimal surface problem.

• Journal of Chest Surgery
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• v.17 no.1
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• pp.118-124
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• 1984

Congenital Cystic Adenomatiod Malformation (C.C.A.M.) is rare, but one of the most common congenital pulmonary anomalies that cause acute respiratory distress in the newborn infants. It is characterized and differentiated from the diffuse pulmonary cystic disease pathologically, i.e. adenomatoid appearance due to marked proliferation of the terminal respiratory components. An 2/12 year old male patient was suffered from respiratory distress and cyanosis on crying since birth, but no specific therapy was given. With progression of symptoms, he came to Korea University Hospital for further evaluation and then transfered to Dept. of Chest Surgery for operative correction under the impression of Congenital Obstructive Emphysema suggested by a pediatrician. On gestational and family history, there was nothing to be concerned such as congenital anomaly. Physical examinations showed; moderate nourishment and development (Wt. 5.5kg), cyanosis on crying, both intercostal and lower sternal retraction on inspiration, Lt. chest building with tympany, Rt. shifting of cardiac dullness, decreased breathing sound with expiratory wheezing on entire Lt. lung field, decreased breathing sound on Rt. upper lung filed, and tachycardia. The remainders were nonspecific. Laboratory findings were normal except WBC $14000/mm^3$ (lymphocyte 70%), Hgb 9.8m%, Hct 28%, negative Mantaux test, and sinus tachycardia and counter-clockwise rotation on EKG. Preoperative simple Chest PA revealed marked hyperlucent entire Lt. lung, herniation of Lt. upper lobe to Rt., collapsed Rt. upper lobe, tracheal deviation and mediastinal shifting to Rt., and no pleural reaction. At operation, after Lt. posterolateral thoracotomy, 4th rib was resected. Operative findings were severe emphysematous changes limited to both lingular segmentectomy was done. The resected specimen showed slight solidity, measuring $8{\times}4.5{\times}2cm$ in size, and small multiple cystic spaces filled with air. Microscopically, entire tissue structures were glandular in appearance, cyst were lined by ciliated columnar epithelium, and occasional cartilages were noted around the cystic spaces. Bronchial elements were dilated but normal pattern on histologically. The patient had a good postoperative courses clinically and radiologically, and discharged on POD 10th without event. The authors report a case of Cogenital Cystic Adenomatoid Malformation (C.C.A.M.)

• Journal of Korean Association for Spatial Structures
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• v.7 no.5
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• pp.75-82
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• 2007

The present work measured and analyzed changes in the acoustics of a sound field which has a retractable ceiling. An 1/20 scale model of an openable space was built and measurement was carried out by varying the opened area of a ceiling. The most widely used room acoustic and design parameters, RT, EDT, and D50 were investigated. The results suggest that the use of RT as an acoustic design parameter may not be proper in an openable space and further it is likely to mislead the initial acoustic design of such spaces. It is mainly due to the characteristics of RT in which non-exponential decay processes are linearly fitted. Early decay times were found to be decreased in proportion to increaing the ratio of opened area. D50, an index of speech intelligibility, was effectively shows the influence of openings on the acoustics. It is also found that EDT and D50 at the seats, not directly exposed to the opened part of a ceiling, were almost linearly decreased in proportion to the ratio of opened area, while little influence was found for the opening ratio larger than 40% at the directly exposed seats to the opened part of a ceiling.

• Development and Reproduction
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• v.4 no.1
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• pp.37-43
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• 2000

Spatiotemporal expression of two isoforms of zonular occludens-1 (ZO-1), tight junctional protein, was examined in mouse testis. By RT-PCR, transcripts encoding two isoforms of ZO-1; ZO-1$\alpha$+ and ZO-1$\alpha$- were detected in testis. Two different forms of ZO-1 antigens with Mr.225 and 2001 KDa were detected in western blot of extract of neonatal to adult testis, coinciding with the result of RT-PCR. The relative amount of ZO-1 $\alpha$- versus 20-1 $\alpha$＋ increased as the mice matured. In immunostaining using the pan antibody which detected both isoforms, ZO-1 was localized in the intercellular spaces in the Sertoli cell - Sertoli cell contacts in periphery of seminiferous tubule as well as Sertoli cell - germ cells contacts within the seminiferous tubule. The expression of ZO-1 was ubiquitous in both junctional area and cytoplasm of seminiferous tubule components. However, more intense signals were found in Sertoli cell junctional areas according to sexual maturation. The changes in the relative amount of both isoforms and spatial distribution of ZO-1 at the periphery of seminiferous tubule might be important for functional appearance of blood testis barrier and spermatogenesis.

• Journal of Korean Association for Spatial Structures
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• v.11 no.1
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• pp.67-75
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• 2011

The present work investigate the effect of sound reinforcement systems on the acoustics of a large dome stadium using a computer simulation. The acoustics of a dome stadium was predicted analyzed by varying room absorption, as well as the configuration of speakers including their directivity, installed height, and numbers. It was found that both D50 and RASTI were improved by increasing room absorption. Larger EDTs were observed according to the increase of room absorption at mid and high frequencies. On the other hand, RT did not show any significant correlation with the changes in room absorption, which might be the effect of a forced linear fitting for non -linear energy decay process. With respect to the speaker configuration, the speech intelligibility of a sound reforcement system installed at higher placed more relied upon their directivity rather than room absorption, Also, lower placing of speakers was found to be effective in decreasing RTs regardless of room absorption.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.589-592
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• 2008

Running title: A plunging ranula extended into parapharyngeal space Ranulas are lesion of sublingual gland origin, which occur in the floor of the mouth. Most ranulas, whether simple or plunging, are pseudocysts without and epithelial lining and ranulas have higher levels of salivary amylase and protein content. They can be classified into two types based on their extent: simple ranulas, confined to the sublingual space and plunging ranula which extend into adjacent spaces. Plunging ranula requires differential diagnosis with other lesions (neuroma, monomorphic adenoma, hemangioma, lipoma, dermoid cyst, lateral cervical cyst). The patient was diagnosed as plunging ranula. We experienced 17 years old male, visited to our department, who complain Rt. cervical swelling and in MRI view, this lesion involved sublingual, submadibular, parapharyngeal, skull base. We experienced a rare case of plunging ranula, extended into parapharyngeal space. We report the case.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.2
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• pp.45-52
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• 2019

BEMS(Building Energy Management Systems) have been applied to office buildings and collect relevant building energy data, e.g. temperatures, mass flow rates and energy consumptions of building mechanical systems and indoor spaces. The aforementioned measured data can be beneficially utilized for developing data-driven machine learning models which can be then used as part of MPC(Model Predictive Control) and/or optimal control strategies. In this study, the authors developed ANN(Artificial Neural Network) models of an AHU (Air Handling Unit) and a chiller for a real-life office building using BEMS data. Based on the ANN models, the authors developed optimal control strategies, e.g. daily operation schedule with regard to optimal start and stop of the AHU and the chiller (500 RT). It was found that due to the optimal start and stop of the AHU and the chiller, 4.5% and 16.4% of operation hours of the AHU and the chiller could be saved, compared to an existing operation.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.4
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• pp.193-202
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• 2022

Manholes and underground spaces are installed to manage the buried heat transport pipes of the district heating system, and the corrosion damage of the equipment placed in this space often occurs. The purpose of this work is to identify locations with a high risk of corrosion damage in the air vent and to establish preventive measures based on precise analysis via sampling of heat transport pipes and air vents that have been used for about 30 years. The residual thickness of the air vent decreased significantly by reaching ~1.1 mm in thickness, and locations of 60~70 mm away from a transport pipe were the most vulnerable to corrosion. The energy dispersive X-ray spectroscopy (EDS) analysis was performed in the corroded oxides, and it was found that chloride ion was contained in the corrosion products. Anodic polarization tests were carried out on the air vent materials (SPPS250, SS304) with varying the amounts of chloride ions at two different temperatures (RT, 80℃). The higher concentration of chloride ions and temperature are, the lower corrosion resistances of both alloys are.