• Advances in Energy Research
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• v.6 no.2
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• pp.91-101
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• 2019

This paper proposes an efficient data-driven approach to build models for predicting energy consumption in buildings. Data used in this research is collected by installing humidity and temperature sensors at different locations in a building. In addition to this, weather data from nearby weather station is also included in the dataset to study the impact of weather conditions on energy consumption. One of the main emphasize of this research is to make feature selection independent of domain knowledge. Therefore, to extract useful features from data, two different approaches are tested: one is feature selection through principal component analysis and second is relative importance-based feature selection in original domain. The regression model used in this research is gradient boosting regression and its optimal parameters are chosen through a two staged coarse-fine search approach. In order to evaluate the performance of model, different performance evaluation metrics like r2-score and root mean squared error are used. Results have shown that best performance is achieved, when relative importance-based feature selection is used with gradient boosting regressor. Results of proposed technique has also outperformed the results of support vector machines and neural network-based approaches tested on the same dataset.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.231-242
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• 1983

A clinical study was performed on 75 cases of the esophageal cancer and benign esophageal diseases experienced at Department of thoracic & cardiovascular surgery, School of Medicine, Keimyung University during 3 year period from 1978 to 1982. Of 75 cases of the surgical esophageal diseases, there were 35 patients of the esophageal cancer. 17 patients of benign esophageal stenosis, 10 patients of esophageal perforation, 4 patients of diverticulum. 3 patients of achalasia, 2 patients of congenital T-E fistula, one of upper esophageal web, one of esophageal foreign body, one of leiomyoma and patient of hemangioma. First, esophageal carcinoma was more frequent in men than in women by a ratio of five to one, and the peak incidence occurred in the 5th to 6th decade. Dysphagia was the most common symptom in 88.6 percent of our cases. The tumor was located mostly in the middle & the lower one third [91.4%]. The histological diagnosis was made in 35 cases. The squamous cell carcinoma was the most common [82.9%] and the rest was the adenocarcinoma in the lower one third [17.1%]. Thirty-five cases were operated and resection was feasible in the twenty-five patients [71.4%] with 2 cases of hospital mortality [5.7%]. All but two of the esophageal stenosis were caused by corrosive esophagitis and ages ranged from 7 to 70 years with average age of 32 years. Corrective operations were performed on 17 patients of esophageal stenosis of whom 12 patients had esophagocologastrostomy, 3 patients esophagogastrostomy and in non-corrosive esophageal stenosis one case and esophagoplasty and another case had release of external compression. There was one complication of stenosis of the esophageal perforation were traumatic in five cases, empyema in three cases, caustics in one case and postemetic in one case. 10 patients of the esophageal perforation underwent operation: primary closure in 5 cases, two staged colon interposition in 2, esophagogastrostomy in 1 and closed thoracotomy in 2 cases There were 2 complications of leakage of anastomosis sites in postoperative period. 4 patients of traction type of diverticulum underwent diverticulectomy & 3 patients of achalasia underwent modified Heller`s operation. 2 patients of congenital esophageal atresia had distal tracheoesophageal fistula & underwent one staged operation with the results of one death caused by pneumonia. Upper esophageal web had divulsion through the esophagoscope and foreign body in upper esophagus was removed through cervical esophagotomy. One case of leiomyoma in esophagus had esophagectomy and reconstruction with right colon. And one case of hemangioma in esophagus had esophagectomy & esophagogastrostomy.

• The Korean Journal of Community Living Science
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• v.21 no.4
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• pp.619-631
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• 2010

The purpose of this study is to segment and examine urban farmers behavior by applying a two-step cluster analysis and multi-nominal logit model. The data were collected by a telephone survey with two-staged stratified random sampling in the cities around the country for the purpose of acquiring representative data. Respondents were asked to describe their awareness of urban agriculture, their agricultural activity, and sociodemographic characteristics. Among 2,000 cases, 381 cases(19.1%) which were of participants in urban agriculture were analysed in SPSS. From the findings, 27.3% of respondents had heard the word 'urban agriculture', and 25.5% of them regarded themselves as urban farmers. Four different clusters were derived from two-step clusters based on motive, place, companion, area and hours. They were 'Large scale hobby farming(cluster 1)', ‘Weekend farm/ hobby farming(cluster 2)', 'Land/ Self-supporting farming(cluster 3)', and 'Small scale hobby farming(cluster 4)'. The result of multinomial logistic regression showed that there were significant differences among these four segmented groups in terms of age, city size and housing type. In other words, there is quite a possibility that urbanites select different urban farming types according to their socio-demographic profiles. Therefore, the urbanite profiles can be used as the basis for promoting policy of several urban agriculture types. According to the result, policy directions for facilitating urban agriculture were presented.

• Korean Journal of Head & Neck Oncology
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• v.25 no.1
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• pp.39-42
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• 2009

Wide excision for curative treatment of malignant tumor on periauricular area often leads to loss of the external ear. But the auricle has rich vascular supply, Conservation of auricular contour is possible through salvage and engineering of remained auricular tissue. We experienced two cases of auricular salvage after wide excision of malignant tumor. In the first case, we performed two-staged technique. In first step, we covered soft tissue defect on periauricualr area with the anterolateral thigh free flap and remained auricle was floating over the flap after split-thickness skin graft was applied on it's posterior raw surface because it's survival was not confirmed. Second step was reposition of remained auricule on the anterolateral thigh flap. In the second case, we packed in periauricular dead space and external auditory canal with temoporalis muscle and temporoparietal fascial flap and then covered the flap with split thickness skin graft. In these two cases, there were no recurrence of tumors and we obtained cosmetically & functionally satisfactory results.

• Hip & pelvis
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• v.35 no.1
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• pp.32-39
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• 2023

Purpose: A staged revision with placement of a temporary antibiotic-loaded cement spacer after removal of the implant is the "gold standard" for treatment of chronic prosthetic joint infection (PJI). It enables local delivery of antibiotics, maintenance of limb-length and mobility, easier reimplantation. However, bacterial colonization of spacers and mechanical complications can also occur. The aim of this study is to evaluate functional results and infection control in two-stage treatment of total hip arthroplasty (THA) PJI with and without a spacer. Materials and Methods: A retrospective review of 64 consecutive patients was conducted: 34 underwent two-stage revision using a cement spacer (group A), 30 underwent two-stage revision without a spacer (group B). At the final follow-up, functional evaluation of patients with a THA in site, without PJI recurrence, was performed using the Harris hip score (HHS). Measurement of limb-length and off-set discrepancies was performed using anteroposterior pelvic X-rays. Results: Most patients in group B were older with more comorbidities preoperatively. Thirty-three patients (97.1%) in group A underwent THA reimplantation versus 22 patients (73.3%) in group B (P<0.001). No significant differences in limb-length and off-set were observed. The results of functional evaluation performed during the final follow-up (mean, 41 months) showed better function in patients in group A (mean HHS, 76.3 vs. 55.9; P<0.001). Conclusion: The use of antibiotic-loaded cement spacer seems superior in terms of functional outcomes and reimplantation rate. Resection arthroplasty might be reserved as a first-stage procedure in patients who are unfit, who might benefit from a definitive procedure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.330-339
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• 2008

Ground-based interceptors(GBI) comprise a major element of the strategic defense against hostile targets like Intercontinental Ballistic Missiles(ICBM) and reentry vehicles(RV) dispersed from them. An optimum design of the subsystems is required to increase the performance and reliability of these GBI. Propulsion subsystem design and optimization is the motivation for this effort. This paper describes an effort in which an entire GBI missile system, including a multi-stage solid rocket booster, is considered simultaneously in a Genetic Algorithm(GA) performance optimization process. Single goal, constrained optimization is performed. For specified payload and miss distance, time of flight, the most important component in the optimization process is the booster, for its takeoff weight, time of flight, or a combination of the two. The GBI is assumed to be a multistage missile that uses target location data provided by two ground based RF radar sensors and two low earth orbit(LEO) IR sensors. 3Dimensional model is developed for a multistage target with a boost phase acceleration profile that depends on total mass, propellant mass and the specific impulse in the gravity field. The monostatic radar cross section (RCS) data of a three stage ICBM is used. For preliminary design, GBI is assumed to have a fixed initial position from the target launch point and zero launch delay. GBI carries the Kill Vehicle(KV) to an optimal position in space to allow it to complete the intercept. The objective is to design and optimize the propulsion system for the GBI that will fulfill mission requirements and objectives. The KV weight and volume requirements are specified in the problem definition before the optimization is computed. We have considered only continuous design variables, while considering discrete variables as input. Though the number of stages should also be one of the design variables, however, in this paper it is fixed as three. The elite solution from GA is passed on to(Sequential Quadratic Programming) SQP as near optimal guess. The SQP then performs local convergence to identify the minimum mass of the GBI. The performance of the three staged GBI is validated using a ballistic missile intercept scenario modeled in Matlab/SIMULINK.

• Journal of the Korean Society of Food Culture
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• v.15 no.1
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• pp.17-28
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• 2000

This paper is an effort to describe dietary behaviors to keep them healthy among adults. A probability sample was drawn from residents aged between 15 and 60 living in Ulsan City area through a multi-staged cluster sampling method. The data collected by face-to-face interview includes 1,232 respondents. Both univariate and bivariate analyses were employed to describe the dietary behaviors. The dietary behaviors in this study includes preference of taking fat-part of meat, fried food, salty food, hot-taste food, drinking coffee and milk, and taking supplementary medicine. About half of the respondents reported to take fat removed when eating meat, and more than 68% of them preferred not to take any kinds of fried food. With respect to preference of salty and hot-taste food, 39.6% of the respondents take medium-salty and 39.4% do hot-taste food. A third of the respondents drink two-four cups of coffee a day. Those who reported not to drink milk at all were prevalent(37.4% of the respondents) than expected. However, less than 20% of the respondents reported to have any kinds of supplementary health food in a year. These dietary behaviors were examined by sociodemographic characteristics for bivariate analyses.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.663-671
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• 2005

Distributed operation of overall structural design process, by which product and process optimization are implemented, is presented in this paper. The database-interconnected multilevel hybrid method, in which the conventional design method and the optimal design approach are combined, is utilized there. The method selectively takes the accustomed procedure of the conventional method in the conceptional framework of the optimal design. Design conditions are divided into primary and secondary criteria This staged application of design conditions reduces the computational burden for large complex optimization problems. Two kinds of numeric and graphic processes, are simultaneously implemented on the basis of concurrent engineering concepts in the distributed environment of PC networks. Numerical computation on server and graphic works on independent client are communicated through message passing. Numerical design is based on the optimization methodology and the drawing process is carried out by AutoCAD using the AutoLISP programming language. The prototype design experimentation for some steel trusses shows the validity and usability of the method. This study has sufficient adaptability and expandability in methodology, in that it is based on general theory and industry standard systems.

• Archives of Reconstructive Microsurgery
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• v.24 no.2
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• pp.41-49
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• 2015

Free or pedicled vascularized fibular grafts (VFG) are useful for the reconstruction of large skeletal defects, particularly in cases of scarred or avascular beds, or in patients with combined bone and soft tissue defects. Compared to non-VFG, VEG, which contains living osteocytes and osteoblasts, maintains its own viability and serves as good osteoconductive and osteoinductive graft. Due to its many structural and biological advantages, the free fibular osteo- or osteocutaneous graft is considered the most suitable autograft for the reconstruction of long bone defects in the injured extremity. The traditional indication of VFG is the long bone and soft tissue defect, which cannot be reconstructed using a conventional operative method. Recently, the indications have been widely expanded not only for defects of midtibia, humerus, forearm, distal femur, and proximal tibia, but also for the arthrodesis of shoulder and knee joints. Because of its potential to allow further bone growth, free fibular epiphyseal transfer can be used for the hip or for distal radius defects caused by the radical resection of a tumor. The basic anatomy and surgical techniques for harvesting the VFG are well known; however, the condition of the recipient site is different in each case. Therefore, careful preoperative surgical planning should be customized in every patient. In this review, recently expanded surgical indications of VFG and surgical tips based on the author's experiences in the issues of fixation method, one or two staged reconstruction, size mismatching, overcoming the stress fracture, and arthrodesis of shoulder and knee joint using VFG are discussed with the review of literature.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2527-2545
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• 2016

Measuring the similarity of given samples is a key problem of recognition, clustering, retrieval and related applications. A number of works, e.g. kernel method and metric learning, have been contributed to this problem. The challenge of similarity learning is to find a similarity robust to intra-class variance and simultaneously selective to inter-class characteristic. We observed that, the similarity measure can be improved if the data distribution and hidden semantic information are exploited in a more sophisticated way. In this paper, we propose a similarity learning approach for retrieval and recognition. The approach, termed as LDA-FEK, derives free energy kernel (FEK) from Latent Dirichlet Allocation (LDA). First, it trains LDA and constructs kernel using the parameters and variables of the trained model. Then, the unknown kernel parameters are learned by a discriminative learning approach. The main contributions of the proposed method are twofold: (1) the method is computationally efficient and scalable since the parameters in kernel are determined in a staged way; (2) the method exploits data distribution and semantic level hidden information by means of LDA. To evaluate the performance of LDA-FEK, we apply it for image retrieval over two data sets and for text categorization on four popular data sets. The results show the competitive performance of our method.