• ETRI Journal
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• v.39 no.6
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• pp.859-865
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• 2017

This paper presents a method for determining the optimum active-area width (OAW) of solar cells in a module architecture. The current density-voltage curve of a reference cell with a narrow active-area width is used to reproduce the current density profile in the test cell whose active area width is to be optimized. We obtained self-consistent current density and electric potential profiles from iterative calculations of both properties, considering the distributed resistance of the contact layers. Further, we determined the OAW that yields the maximum efficiency by calculating efficiency as a function of the active-area width. The proposed method can be applied to the design of the active area of a dye-sensitized solar cell in Z-type series connection modules for indoor and building-integrated photovoltaic systems. Our calculations predicted that OAW increases as the sheet resistances of the contact layers and the intensity of light decrease.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.22 no.4
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• pp.217-239
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• 2018

This paper examined the MHD and thermal behavior of unsteady mixed convection flow of a rotating fluid in a porous parallel plate channel in the presence of Hall current and heat source. The exact solutions of the concentration, energy and momentum equations are obtained. The influence of each governing parameter on non dimensional velocity, temperature, concentration, skin friction coefficient, rate of heat transfer and rate of mass transfer at the porous parallel plate channel surfaces is discussed. During the course of numerical computation, it is observed that as Hall current parameter and Soret number at the porous channel surfaces increases, the primary and secondary velocity profiles are increases while the primary and secondary skin friction coefficients are increases at the cold wall and decreases at the heated wall. In particular, it is noticed that a reverse trend in case of heat source parameter.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.386-388
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• 2003

We are developing a web-based movie recommender system that catches and reasons with user profiles and ratings to recommend movies. In the paper, we outline the current status of our implementation with particular emphasis on the mechanisms used to provide effective recommendations. Social recommender systems collect ratings of items from many individuals and use nearest-neighbor techniques to make recommendations to a user. However, these methods only depend on the ratings and ignore other useful information. Our primary concern is to provide an approach that can recommend the movies based on not only the user ratings but also the significant amount of other information that is available about the nature of each items - such as cast list or movie genre. We experimentally evaluate our approach and compare them to conventional social filtering, which suggests merits to our approach.

• Proceedings of the Microbiological Society of Korea Conference
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• 2003.05a
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• pp.77-79
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• 2003

Current therapeutic strategies far anthrax have had no significant impact on anthrax mortality over the last several decades. This study used a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) discovery platform to generate protein expression profiles in search of overexpressed proteins in murine macrophage cells (RAW264.7) which infected with Bacillus anthracis spores as potentially novel molecular targets. Two differentially expressed proteins were identified in infected murine macrophage cells as Syndapin and CDC46, respectively. Syndapins are potential links between the cortical actin cytoskeleton and endocytosis. Other two proteins were identified from murine macrophage cells infected with avirulent spores as ITBG-2 (CD18) and HSPA5, respectively. These data demonstrate the feasibility of using a MALDI-TOF platform to generate protein expression profiles and identify potential molecular targets for anthrax therapeutics.

• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.46-59
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• 2002

The main purpose of this study is to investigate the variation of tool electrode edge wear and machining performance outputs, namely, the machining rate (workpiece removal rate), tool wear rate and the relative wear, with the varying machining parameters (pulse time, discharge current and dielectric flushing pressure) in EDM die sinking. The edge wear profiles obtained are modeled by using the circular arcs, exponential and poller functions. The variation of radii of the circular arcs with machining parameters is given. It is observed that the exponential function models the edge wear profiles of the electrodes, very accurately. The variation of exponential model parameters with machining parameters is presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.902-905
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• 2003

It's general a trend to use the load/unload mechanism in the small form factor HDD, like 2.5", 1.8" and 1.0". The load/unload mechanism has tittle opportunity of head/media contact during the disk spin-up and down. However, the load/unload mechanism needs the precise integration technology with slider, suspension ramp, load/unload velocity and so on, and all of these components should be designed simultaneously, not an individually. In this paper, we measured the load/unload velocity in the drive level, and executed the load/unload dynamics with this velocity profiles. We could find the current load/unload mechanism suitable to the long load/unload test.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.1
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• pp.46-50
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• 1990

Heteroface AlGaAs/GaAs drift solar cells with an active area conversion efficiency of 15.9% under one sun and AM 1.5 condition have been grown by molecular beam epitaxy(MBE). These drift solar cells have graded doping profiles in the base and emitter regions. The cells have a short circuit current density (Jsc) of 19.00 mA/cm\ulcorner an open circuit voltage(Voc) of 0.93 V, and f fill factor(FF) of 0.78, respectively. Conventional solar cells with fixed doping profiles were also grown by MBE for comparison with the drift solar cells. Even though the fabrication cost of MBE grown solar cell is higher, the expected highest conversion efficiency of the single or multiple cells could compensate for the increased cost, particularly in case of space applications.

• Journal of the Korea Society for Simulation
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• v.13 no.1
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• pp.51-63
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• 2004

Current distributed systems are attacked from the outside as well as in which new intrusions are occurred. In particular there is a growing but largely unnoticed intrusion threat due to the emerging middleware technologies such as CORBA, WAP, XML support, and enterprise application integrators. In order to cope with these attacks, intrusion tolerance technology is introduced. Intrusion tolerance technology means that it can provide services normally although attacks are occurred into system. There are intrusion tolerance architectures such as ITUA, HACQIT, SITAR, and so on as a part of DARPA project. In this paper, we analyze and discuss existing intrusion tolerance architectures with respect to intrusion tolerance technology. Also, we extract intrusion tolerant requirements, which are required to develop ,intrusion tolerant system. We propose UML-IT(Intrusion Tolerance) profiles and specify intrusion tolerant software by applying UML-IT profiles.

• International Journal of Railway
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• v.8 no.1
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• pp.1-4
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• 2015

An accurate measurement of the train-track interaction forces is important for track performance evaluation. In the field calibration test as a wheel load measurement process, the calibration system creates a different boundary condition in comparison with that in the train wheel passage. This study aims to evaluate a reliability of the field calibration test in the process of wheel load measurement. Finite element models were developed to compare the deformed shapes, bending moment and shear force profiles on the rail section. The analysis results revealed that the deformed shapes and their associated bending moment profiles on the rail are significantly different in two numerical simulations of the calibration test and the train wheel load passage. However, the shear stress profile on the rail section of the strain gauge installation in the field was almost identical, which may imply that the current calibration test is sufficiently reliable.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.4
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• pp.149-154
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• 2018

Risk Based Oversight is a way of performing oversight, where planning is driven by the combination of risk profile and safety performance. Risk Based Oversight enables prioritization and allocation of State's safety management resources commensurate with the safety risk profile of each service provider. This paper presents the concept of Risk Based Oversight and applies it to the current Korean aviation safety oversight process. In particular, this study presents a method for generating operating profiles, one of the key concepts of Risk Based Oversight. Operations Specifications of Part 121 Airlines can generate operating profiles. In this study, a practical study was conducted to generate the operating profile and scoped DCTs using Part 121 Airlines's Operations Specifications.