• Science of Emotion and Sensibility
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• v.17 no.2
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• pp.77-84
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• 2014

Menstruation being an inevitable phenomenon for every women, reducing the discomfort during the menstruation period is one of the important issues for women's well-being. This study was conducted through user evaluations on disposable pads and reusable pads to comprehend the discomfort factors of the sanitary pads and to provide basic information for improvement. Negative symptoms of the reponses on menstruation outnumbered the positive aspects, and the results suggested that menstruation period was perceived as a painful experience to women. There were difference between the negative and positive responses regarding the designs, functions, fittings, wearing sensations. and disposabilities of disposable pads and reusable pads. While disposable pads had the strength of convenient use, it had the weakness of wearing sensation, and while reusable pads had the strength of wearing sensation, it had the weakness of inconvenient keeping. When designs reflecting these results are made, it is expected to bring a synergy effect by bringing both a more pleasant menstruation period for the consumers and eventual profit to the manufacturers.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.138-151
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• 2018

In this study, development information and technologies for reusable launch vehicles were surveyed. We investigated the reusable launch vehicles developed in various countries and analyzed their recovery technologies. In particular, we focus on the technologies of the Falcon 9 of SpaceX and the New Shepard of Blue Origin, which have succeeded in several flight experiments. Moreover, we explain the control algorithms for each flight condition. Finally, we discuss the reusable technologies that can be applied to the Korean Space Launch Vehicle to reduce the launch cost.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.1-9
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• 2019

Recently, in the space market, there has been a rapid reduction of the launch price. The major reason is that a few commercial companies, especially SpaceX, began to enter into the space market about ten years ago, which has changed the space market from monopolization to competition, and accelerated the adoption of commercial efficiency in the technology and management. Also, the successful landing and recovery of a first stage in 2016 by SpaceX proved to be a prelude to opening a new era of reusable launch vehicles, and SpaceX declared the groundbreaking launch price through using the reusable launch vehicle. This study calculates the total launch cost required to put a certain satellite into the LEO, compares the launch cost in three cases with different payload weights, and reviews the impacts of the payload on the cost effectiveness of a reusable vehicle. The total launch cost is divided into 6 subsections cost, namely development cost, production cost, refurbishment cost, operation cost, fixed-cost of factory and launch site, and insurance cost. The cost estimation relationships used in the calculation are taken from the commonly proven cost models such as TRANSCOST.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.8
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• pp.627-636
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• 2021

This paper deals with a study for the guidance control of reusable launch vehicle. For this purpose, modeling of the equation of motion of a reusable launch vehicle with 6 degrees of freedom was performed. With this model, an optimal re-entry path was created and a path-following guidance control simulation was performed to follow the optimal re-entry path. For the design of the path-following guidance controller, the attitude controller applying a time-delay technique that is resistant to modeling uncertainty, disturbance and failure. And the nonlinear path-following guidance law were used. Guidance control simulation using a classical PD controller was performed and compared with the guidance control simulation of a reusable launch vehicle applying a time delay technique.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.42-45
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• 2006

A new and reusable energy source is water-treatment sludges. There is a significant need for understanding the characteristics of sludge combustion related to improving efficiency and ensuring the safety of this new energy source. Because sludges are composed of solids and gas mixture, the combustion of the mixture may become quite complex. Not only decomposition of conventional organic elements but also dust explosion may be important during the process of converting sludges into a new and safe form of energy. Sludge combustion mainly involves hydrogen, methane, hydro carbons, carbon, and organic particles. Dust explosion during the gasification stage may depend on the surrounding temperature and the composition of gases. The uncertainty in the explosive behavior of energetic source is noted in this work. We study the explosion characteristics of sludge combustion while the reusability of sewage sludges as a new form of energy is also investigated.

• IE interfaces
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• v.15 no.2
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• pp.182-188
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• 2002

Clustering is widely used in various fields in order to investigate structural characteristics of the given data. One of the main tasks of clustering is to partition a set of objects into homogeneous groups for the purpose of data reduction. In this paper a simple but computationally efficient clustering procedure is devised and some statistical techniques to validate its clustered results are discussed. In the given procedure, the proper number of clusters and the clustered groups can be determined simultaneously. The whole procedure is applied to a practical clustering problem for the classification of reusable fuels in nuclear power plants.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.107-117
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• 1997

It is use in many researches that the s/w quality evaluation evaluates the developing system or the developed system, updates the problems and selects the reusable components from source code. In this paper, we propose the objective metric functions which can evaluate the reusability of candidates classes with the KHR system[11] and select a proper candidate. The quantitative quality we proposed have merits to compare and to evaluate the reusable candidates classes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.868-877
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• 2013

This paper will provide the cloud service based on PaaS that can enhance reusability of development in the cloud computing environment. The cloud service based on PaaS is the cloud service of platform in the side of development, which provide the reusable framework service that is beyond the existing development tool or management tool service. This reusable framework service will be enhanced reusability using a variety of distributed services.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.143-147
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• 2006

Several regulations on converting reusable products are established in many countries, due to the emphasis on environmental issues on manufacturing. Many companies consider reusable and returned items in addition to purchasing new items. In this paper we suggest several algorithms to determine the near optimal quantities of items for converting and new items for purchasing. The reusable items are converted into end items, each facing normally distributed demand in a single period of interest. We develop a mathematical model and a genetic algorithm(GA) to compare the number of convertible units and new items to be purchased. Computational results demonstrate the efficiency of the developed algorithms.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.85-94
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• 1999

Reconfiguration, expansion, or new establishment of FMS requires the availability of a shop floor control (SFC) system relevant to the FMS since it is closely related with the hardware component of FMS. Due to the expensive cost of its development, significant research efforts have been made to develop an SFC system that is reusable. This paper presents Abstract Machine Tool (AMT) approach applied to develop an SFC sytem that is reusable without additional programming. The AMT model enables us to design the SFC system independently of the hardware-dependent attributes of euqipment; an AMT models a workstation by abstraction and presents an equipment-independent interface to machining cell controller. Specifically, we describe how we formalize the interfaces among equipment in order to build an AMT and how we design the machining cell control software based on AMT models. We also present MACHINIST the machining cell control system for IAE-FMS plant as an implementation example.