• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.199-204
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• 2014

W-Project is 70-story mixed-use residential building complex project in Busan, the second biggest city in South Korea. As it is a high rise building complex located at the coast, the residents have great ocean view from the height. Though, there were many difficult challenges to be solved to secure structural safety and meet the serviceability requirements. As it is located on the reclaimed land, securing the foundation bearing capacity on soft soil is the first issue to be solved for the stable structure. W-Project. Busan on the way usual track of typhoon, wind load on structure is also critical for structural safety and serviceability for occupants due to wind vibration. This paper will address process of lateral load resisting structural system of W-Project.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.461-466
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• 2000

To improve the quality of concrete, we usually consider the reduction of water/cement ratio, the increase of concrete cover depth and the use of mineral admixtures. Reportedly, the use of admixtures make concrete more durable and tighten against water. But, it is needed to study more about the relationship between the admixtures and the chloride ion diffusion. Therefore, in this study, we focused on the chloride ion diffusion properties of the pozzolanic admixtures such as fly-ash, slag and silica fume which are known as being useful on chloride attack resistance when mixed into mortar or concrete. Furthermore, we treed to analyze the correlation between mortar and concrete using the admixture, which is useful for analyzing chloride ion diffusion mechanism.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.37-42
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• 2006

The paper discusses the combined use of softwood and eucalyptus kraft pulps in the production of printing and writing papers. Looking for process and paper quality optimization, refining pilot plant trails were carried to identify the effects of refining type (mixed or separate) and intensities (specific edge load), and also furnish composition (amount of each pulp in mixture) on final paper quality and process costs. The basic effects on pulp fibers were evaluated against paper quality properties, such as physical strengths, bulk, vessel picking, opacity and porosity, as well as the interactions with papermaking process, such as estimates of paper machine runnability, paper breaks and industrial refining control. The results show that the furnish composition and the type of refining has a significant effect on properties related with both final paper quality and total costs. The best alternative for printing and writing papers was identified for mixed refining, under the lowest refining intensity, and with the highest dosage of eucalyptus pulp.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.7
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• pp.1125-1129
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• 2015

Increasing peak load is one of the major concerns about operation of urban railroad systems. Since ESSs (Energy Storage Systems) have a great potential for shaving the peak load, there has been a growing interest in the use of ESS for peak load reduction. Also, ESS can be optimally scheduled to minimize the electricity purchasing cost under a given ToU (Time-of-Use) tariff by taking advantage of electricity price difference between peak and off-peak time. This paper presents a Mixed Integer Programming (MIP)-based ESS scheduling method to minimize the electricity purchasing cost under a ToU tariff for an urban railroad system.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.619-624
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• 2014

This paper introduces a robot-based learning system which is designed to teach multiplication to children. In addition to a small humanoid and a smart device delivering educational content, we employ a type of mixed-initiative operation which provides enhanced multi-modal cognition to the r-learning system through human intervention. To investigate major factors that influence people's intention to use the r-learning system and to see how the multi-modality affects the connections, we performed a user study based on TAM (Technology Acceptance Model). The results support the fact that the quality of the system and the natural interaction are key factors for the r-learning system to be used, and they also reveal very interesting implications related to the human behaviors.

• Journal of the Korean Institute of Educational Facilities
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• v.15 no.4
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• pp.14-25
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• 2008

The Purpose of this study is to find out the renewal methods of Dae-jun railway station areas, focusing on the domestic/foreign case studies of the railway station areas and the possibility of the Industry-University-Institute collaboration in this area. As a result, this study shows that the revitalization for the impact area around rail transit station in the aspect of urban spatial structure, mixed land use, type of facilities and exchanging transit system of mass traffic etc, as well as such non-physical aspects as Industry-University-Institute collaboration and administrative planning. It does so by strengthening ties between hardware and software studies of urban planning and University Facilities planning. Finally this study suggested the strategy for the renewal of impact area around the rail transit stations.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.4
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• pp.373-375
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• 1995

In order to turn the Bag Filter to the Purse Filter, the past system that the adverse reason is removed, the input of synthetic materiality of dust and air is placed down, and the output is placed up has been improved so that any adverse effect shall not be raised. The form of filteration mechanism is changed from a cylinder from, and the dust and air is mixed to make the entry velocity and one person can velocity of the mixed materiality become lower by the use of infinity, and the reception of filteration mechanism has been made reasonably. The dust separated from the filteration mechanism is desceded down, snd the mixde materiality is ascended up. So, a cross point is formed, and a collision and a friction is occurred from its process, and at its result, dust is scattered to stick to a filter cloth, therefore, the loss of pressure shall ont be appeared by cause of the increase of dust-loading.

• International Journal of Reliability and Applications
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• v.14 no.1
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• pp.41-54
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• 2013

In this paper, cost analysis is conducted using inter-failure interval under renewable warranty subject to imperfect repair for multi-component system. One way to model the imperfect repair is to use the quasi-renewal process (Wang and Pham 1996). Two alternative quasi-renewal processes were suggested by Park and Pham (2010) using quasi-renewal process; first is an altered quasi-renewal process with random variable parameter and second is a mixed quasi-renewal process considering replacement service and repair service, simultaneously. In this study, we use the altered and mixed quasi-renewal processes and develop the warranty cost model to obtain the expected value of warranty cost and to help company make important decisions regarding the warranty policy. Numerical examples are used to demonstrate the applicability of the methodology derived in the paper.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.454-457
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• 2010

본 연구에서는 입체/복합도로용 내진신축이음장치를 개발하고 복층구조의 입체/복합도로 JC를 설계하였다. 입체/복합도로용 내진 신축이음장치는 공중관통형 일체구조의 입체/복합도로에서 두 교량을 각각 지지하는 교각과 건물이 서로 다른 방향으로 거동할 때 거동 방향에 상관없이 교량을 주행 중인 차량이 안전하게 교량 상판을 통과할 수 있어 지진 등의 대형사고에 의한 피해를 최소화할 수 있다. 또한 지하형 복층구조의 입체/복합도로는 서로 직교하는 지하도로에 입체교차로를 형성하여 효율적인 지하 도로망을 구축할 수 있으며 지하도로를 건축물 지하주차장과 연결로를 통해 직접 연계함으로써 집객 효과가 매우 높다.

• Communications for Statistical Applications and Methods
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• v.30 no.3
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• pp.331-341
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• 2023

Handling missing values in data analysis is essential in constructing a good prediction model. The easiest way to handle missing values is to use complete case data, but this can lead to information loss within the data and invalid conclusions in data analysis. Imputation is a technique that replaces missing data with alternative values obtained from information in a dataset. Conventional imputation methods include K-nearest-neighbor imputation and multiple imputations. Recent methods include missForest, missRanger, and mixgb ,all which use machine learning algorithms. This paper compares the imputation techniques for datasets with mixed datatypes in various situations, such as data size, missing ratios, and missing mechanisms. To evaluate the performance of each method in mixed datasets, we propose a new imputation performance measure (IPM) that is a unified measurement applicable to numerical and categorical variables. We believe this metric can help find the best imputation method. Finally, we summarize the comparison results with imputation performances and computational times.