• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7A
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• pp.560-568
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• 2012

Spectrum sensing and spectrum decision are the main functions that cognitive radios (CRs) have to perform in order to get the best available spectrum band for the establishment of a wireless communication. These problems are worsened in the presence of users with different demands and spectrum channels with different properties in a heterogeneous network. The primary objective in this work is to design and simulate a new spectrum decision algorithm for heterogeneous cognitive radio system. To this end, first, we consider all cognitive users are separated into different traffic classes according to their Quality of Service (QoS). The cognitive users within one traffic class perform spectrum sensing in centralized group-based cooperative spectrum sensing system and the users of different traffic classes share the sensing results. Second, we propose a novel use of the Analytic Hierarchy Process (AHP) to optimally select available bands according to user requirements and detected spectrum channel characteristics (SCC). In this paper, utility function is used as spectrum decision algorithm. Simulation results demonstrate that the proposed method shows can effectively select the best available spectrum channels with a low complexity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.789-796
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• 2019

If the development of Integrated Logistics Support (ILS) for maintenance of the end step is conducted systematically and efficiently, the weapon system lifecycle can be postponed and the availability can be improved. DEFense CONdition (DEFCON) is maintained as perfect. Nevertheless, like its importance, the guide for maintaining the depot performance is applied differently for each weapon system. The errors that can result cause additional cost, etc. ILS development at depot level maintenance is different from full scale development. Therefore, this study distinguishes the management and deployment section for the development concept. An additional way to perform an efficient development of depot maintenance element when determining the depot maintenance period were presented. This study examined how the Reliability, Availability, Maintainability (RAM), Logistics Support Analysis (LSA), and ILS 11 elements intersect at the depot maintenance sources. An analytical study of concrete adoptable plans was performed. The systematic adoption of a development procedure can make it possible to calculate the adoptable development cost. In addition, it can be helpful for improving the quality level and practical use of work products.

• Journal of Hospice and Palliative Care
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• v.20 no.4
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• pp.221-225
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• 2017

Care for the human spirit is a core component of quality end-of-life care. Logotherapy, based on the premise that the primary motivation of human beings is to find meaning and purpose in life, can be helpful in providing care for patients, families, and loved ones in hospice care. The use of Socratic dialog in posing questions about one's life experiences, values, and attitudes is a useful method of evoking reflection. Guidance for finding meaning, even until one's last moments, can be found in the three categories: (a) tasks or deeds, (b) experiences of love and beauty, and (c) attitudes chosen in spite of a fate that cannot be changed. Self-transcendence, defined as getting outside the self for the good of others, can add meaning to life. A growing body of research concerning meaning-centered therapy is promising for improving spiritual well-being and a sense of meaning and purpose in life.

• Journal of Digital Contents Society
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• v.18 no.3
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• pp.607-612
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• 2017

The use of RaspberryPi in building an embedded system may be difficult for users in understanding the circuit and the hardware cost. This paper proposes a solution that can test the systems virtually. The solution consists of three elements; (i) editor, (ii) interpreter and (iii) simulator and provides nine full modules and also allows the users to configure/run/test their own circuits like real environment. The task of abstraction for modules through the actual circuit test was carried out on the basis of the data sheet and the specification provided by the manufacturer. If we can improve the level of quality of our solution, it can be useful in terms of cost reduction and easy learning. To achieve this end, the electrical physics engine, the level of interpreter that can be ported to the actual board, and a generalization of the simulation logic are required.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1062-1073
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• 2004

We describe a looper controller design for a hot strip finishing mill in steel plants. The main function of the looper system is to balance the mass flow of the strip by accumulating material in the middle of the stands. Another function is to control the strip tension which influences the width of the strip. To ensure strip quality, it is very important to control the tension of the hot strip finishing mill. However, because there is a mutual interaction between the looper angle and the strip tension, it is difficult to control the looper system. Previous researches examined only the operation of a single stand. But it is not sufficient to examine the operation and effect of whole stands because the operation is wholly interdependent. In this paper, we present a full model of the hot strip finishing mill in order to more effectively control strip tension. We propose several control methods for the full-stand hot strip finishing mill, denoted as conventional PI, PI with cross gain, and coefficient diagram method (CDM) PID control. In the real plants, there are some problems by using higher order controllers such as LQ, LQG and H$\_$$\infty$/. By comparison, the PID controller is very simple and easy to apply to all real plants. To that end, we present our findings on PID controls and their potential use in the hot strip finishing mill.

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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• pp.233-239
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• 2010

Supercritical carbondioxide is very effective in removing oils from a variety of seed matrices, devoid of any appreciable amount of phospholipid content. However, the limited solubility of phosphalipids in supercritical carbondioxide leaves behind a potentially valuable by-product in spent seed matrix. Any phospholipid extraction process from the spent matrix must maintain the structure and the quality of phospholipids and must be compatible with the end use of the seed protein meal an animal feed or for human consumption. An initial supercritical carbondioxide extraction of soybean flakes was performed at 32 MPa and $80^{\circ}C$ to extract the oils, leaving the phospholipids in the deflatted soybean flakes, A second step was performed on the defatted soybean flake using $X_{eth}$=0.10, Varying the pressure from 175 MPa to 70.6 MPa and temperature from $60^{\circ}C$ to $80^{\circ}C$. For all supercritical carbon dioxide/ethanol mixture extractions, a fraction rich in phospholipids was obtained. The fractions extracted from defatted soybean flakes were dried and them redissolved in chloroform before HPLC-ELSD analysis. Quantitative and qualitative analysis of phospholipids on soybean seeds, defatted soybean flake, and different extracted phospholipid fractions was carried out, to ascertain the effect of extraction pressure and temperature.

• Journal of Korean Library and Information Science Society
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• v.50 no.3
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• pp.71-95
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• 2019

With high interest in linked data, there are various attempts to accommodate the linked data model in cataloging process. This study intends to discuss how to adopt and make the best use of linked data based bibliographic framework in order to improve the quality of library catalogs and to enhance library services in Korean libraries. To the end, this study focuses on (1) discussion of the meaning of linked data from the library cataloging perspective, (2) tracking best practices for implementing and operating linked data among North American and Europe libraries and bibliographic networks (in detail, constructing various types of ontology, developing linked data model including BIBFRAME and OCLC linked model, and improving retrieval service and interface), and finally (3) exploring problems and the anticipated challenges to transition to the linked data model in Korea. The data for discussion were collected from literature review and case study.

• Elastomers and Composites
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• v.35 no.3
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• pp.205-214
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• 2000

The polyurethane resin was prepared by the reaction of tolylenediisocyanate(TDI) and polypropyleneglycol(PPG). Physical properties of the resin were investigated experimentally. Charging catalyst before TDI-dropping induced the rapid increase of viscosity. On the other hand, charging catalyst after TDI-dropping resulted in mild stability without immoderate generation of heat on reaction. The use of phosphoric acid as catalyst led to low viscosity by restraining side-reaction such as forming of branch-chain, buret reaction and allopanate reaction, but it showed low cross-link density and slow drying. The curing speed was more influenced by structures of molecules rather than NCO/OH ratio. Including PPG 400 over 30 wt % showed excellent adhesive strength due to increase of crosslink density.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.262-268
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• 2008

A compact imaging spectrometer (COMIS) for use in the STSAT3 microsatellite is currently under development. It is scheduled to be launched into a low Sun-synchronous Earth orbit (${\sim}700km$) by the end of 2010. COMIS was inspired by the success of CHRIS, which is a small hyperspectral imager developed for the ESA microsatellite PROBA. COMIS is designed to achieve nearly equivalent imaging capabilities of CHRIS in a smaller (65 mm diameter and 4.3 kg mass) and mechanically superior (in terms of alignment and robustness) package. Its main operational goal will be the imaging of Earth's surface and atmosphere with ground sampling distances of ${\sim}30m$ at the $18{\sim}62$ spectral bands ($4.0{\sim}1.05{\mu}m$). This imaging will be used for environmental monitoring, such as the in-land water quality monitoring of Paldang Lake, which is located next to Seoul, South Korea. The optics of COMIS consists of two parts: imaging telescope and dispersing relay optics. The imaging telescope, which operates at an f-ratio of 4.6, forms an image (of Earth's surface or atmosphere) onto an intermediate image plane. The dispersion relay optics disperses the image and relay it onto a CCD plane. All COMIS lenses and mirrors are spherical and are made from used silica exclusively. In addition, the optics is designed such that the optical axis of the dispersed image is parallel to the optical axis of the telescope. Previous efforts focused on manufacturing ease, alignment, assembly, testing, and improved robustness in space environments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.645-653
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• 2020

Recently studies on how to use the UAV (Unmanned Aerial Vehicle) are actively being conducted, and the National Geographic Information Institute published the 『Work Guidelines for Public Surveying of Unmanned Aerial Vehicles』. However, the guidelines do not provide the optimum shooting conditions required for each application. In this study, we tried to find the suitable shooting conditions for the production of 3D (Three-dimensional) spatial information and orthophoto. To this end, 45 experiments were conducted by various altitudes, overlaps, and camera angles within an above ground level of 150m. For evaluating the 3D modeling by shooting conditions, point densities of 9 verification areas were analyzed, and to evaluate the orthophotos, 1/1,000 digital maps were compared. Considering the quality of the output and the processing time for precise 3D construction, an altitude of 50m, an overlap of 70~80%, and a camera angle of 80~90° are suitable as shooting conditions, and an altitude of 100m and camera angle of 80~90° are suitable for orthophoto generation.