• Journal of the Korea Society for Simulation
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• v.30 no.4
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• pp.9-19
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• 2021

Electronic voting has been recognized as an alternative to complement the limitations of existing paper voting. At the same time, security concerns are being raised. This paper presents a blockchain-based electronic voting and survey system that can guarantee reliability. Our smart contract was created using Solidity on Ethereum which is a blockchain-based distributed computing platform, and the system was implemented in connection with the Javascript based user interface. In addition, in order to protect the personal information of participants, the system is generating hash of the personal data and storing the hash of users for the contract data. Since we exploited different kinds of languages for the system, we derived items of functionality testing and presented the functionality testing result. Moreover, we made use of the Chrome's performance evaluation functionality to see the response time of the blockchain-based system. In addition, we compared the performance with the system which has the same functionality on database. The contribution of this research is design and implementation of blockchain-based electronic voting system and presentation of the functionality and performance simulation result.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.9
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• pp.419-430
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• 2023

Currently, NFTs have no dominant application except for the proof of ownership for digital content, and it also have small liquidity problem, which makes their price difficult to predict. Real estate usually has very high barriers to investment due to its high pricing. Real estate can be converted into NFTs and also divided into small value fungible tokens (FTs), and it can increase the the volume of the investor community due to more liquidity and better accessibility. In this document, we implement and design a system that allows ordinary users can invest on high priced real estate utilizing Black Litterman (BL) model-based Portfolio investment interface. To this end, we target a set of real estates pegged as collateral and issue NFT for the collateral using blockchain. We use oracle to get the current real estate information and to monitor varying real estate prices. After tokenizing real estate into NFTs, we divide the NFTs into easily accessible price FTs, thereby, we can lower prices and provide large liquidity with price volatility limited. In addition, we also implemented BL based asset portfolio interface for effective portfolio composition for investing in multiple of real estates with small investments. Using BL model, investors can fix the asset portfolio. We implemented the whole system using Solidity smart contracts on Flask web framework with public data portals as oracle interfaces.

• Journal of Power System Engineering
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• v.21 no.1
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• pp.70-79
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• 2017

The output power of turbine is greatly affected by the losses generated within the passage. In order to develop a better turbine or loss models, an experimental study was conducted using a linear cascade experimental apparatus. The total pressure loss and flow structures were measured at two cross-sectional planes located downstream of blade row. Measurement was conducted in a steady state for the several different locations of the blade row along the rotational direction. The blade row moved by 20 % of the pitch, and tip clearance was varied from 2% to 8%. Axial-type blades were used and its blade chord was 200mm. A square nozzle was applied and its size was $200mm{\times}200mm$. The experiment was conducted at a Reynolds number of $3{\times}10^5$ based on the chord. Nozzle flow angle sets to $65^{\circ}$ based on the axial direction and the solidity of blade row was 1.38. From the experimental results, the total pressure loss was greatly varied in the receding region than in the entering region. The flow properties within the blade passage were strongly changed according to the location of blade row.

• Archives of design research
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• v.13
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• pp.55-64
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• 1996

Garment is not only a part of formative art that establishes a live shape by wearer but also space modeling which features the solidity based on human body. Hence, beyond the simple meaning of 'wearing clothes', modeling which makes a cubic shape in accordance with human body's movement, is an important element in garment design. This study examined puli-over-typed garment design that owns abundant space sense, taking complex shapes of geometrical diagrams with brief and simple features as a motive. The study aims at seeking after the combination of plane and cubic forms, and exploring formative garments which are further modern and different variance by approaching the natural section of geomentrical facets with tightfitting idea and composition of delicate colors and forms when plane pattern was put on human body.

• The KSFM Journal of Fluid Machinery
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• v.19 no.6
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• pp.5-13
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• 2016

Three-dimensional unsteady numerical analysis has been performed to observe aerodynamic characteristics of a H-rotor. Generally, the structure of the H-rotor is simple but the aerodynamic characteristics are exceptionably complicated since the angle of attacks and incident velocities to a blade are considerably varied according to the azimuth angles and solidities. The blade in the upwind revolution between 0 to 180 degree obtains aerodynamic energy from the free stream but the blade in the downwind revolution between 180 to 360 degree does not. When the rotating speed increases, the blade in the downwind revolution accelerates the air around the blade like a fan and it consumes the energy and shows negative torque in the area. On the other hand, the direction of the free stream is bent because of the interaction between blade the free stream. Therefore, the operation point (highest power coefficient) appears at a lower tip-speed-ratio what it is expected.

• Journal of Pharmaceutical Investigation
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• v.1 no.1
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• pp.70-77
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• 1971

The ointment, had discovered and used from the ancient, have not ever defined to qualitity as the hardness concerned with the absorned With the absorption of the effect of durg through the skin. Auther, for the first time, suggest the apparent logarithmic hardness against the penetration of ointment registered on the pharmacopeia of the Republic of Korea, the results are as the followings. 1. The speciality of this apparent logarithmic hardness ie in proportion for the solidity on the contrary to the penetration of oiniment, and the distribution range of it are between 1.68 to 3.53 for their ointments examined. 2. The specific gravity of the verious ointments according to the apparent logarithmic hardness may be ignore on the calculaiotn, the mean valve of the samples was 2.9303. 3. The determination of apparent logarithmic hardness(H) by the penetration method follows the under equation. $H=log_{10}({\frac{P-0.545h^3}{0.855h^2}})$ where, the h is the penetrate length described centimeter, and p is the weight of the cone.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.8
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• pp.434-440
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• 2002

Switched Reluctance Motor (SRM) has been not commonly used because of the severe noise and vibration, although it has many advantages as solidity and economical efficiency. The origin of the acoustic noise and vibration in SRM's can be broadly classified into two types, mechanical and magnetic. Therefore this paper verifies the origin of vibration induced by radial magnetic forces from various experiments, and then studies the relationship between the output and vibration characteristics of SRM according to switch-on and off angles. Acceleration, torque and efficiency is measured by changing switching angles. From the comparison and analysis of the experimental results, a proper switching angle is presented for both satisfying electric performance and reducing vibration.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.1-7
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• 2011

In the performance test for wind turbines of medium and large, The reference met-mast should be installed for measurement reference wind speed as IEC 61400-12-1 standards and design of booms for mounted an anemometer must be considered exactly. Boom-mounted cup anemometer are influenced by flow distortion of the mast and the boom. Therefore design of booms must be important so that flow distortion due to booms should be kept below 0.5%. But, in some cases at size of met-mast structure, the distance of boom from mast is longer then measurement of wind speed is impossible because of oscillation of boom-mounted anemometer. In this paper, We measured a wind speed at several point from mast and boom and we analyzed the error of wind speed at each point of measurement. Also, we will suggest a correction method using the data curve fitting about errors of wind speed between each point of mounted anemometer.

• The KSFM Journal of Fluid Machinery
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• v.10 no.3 s.42
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• pp.17-24
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• 2007

This paper presents the design procedure of a vertical wind turbine named jet-wheel-turbo turbine and the numerical and experimental verifications. The design parameters such as the rotor inlet angle, the diameter-to-hub ratio, the inlet guide outlet angle and the solidity were optimized to maximize the energy transfer, and to further increase the turbine efficiency by applying the side guide vane and the side opening to the rotor. The maximum power coefficient of 0.59, which is much higher than the ever-designed three-bladed horizontal turbines, was experimentally obtained when the optimal inlet- and side-guide vanes were installed and both sides of the rotor were 80% opened. The maximum power coefficients occur at the tip speed ratio ranging between 0.6 and 0.7. This vertical-axis turbine model can be applied to the large-scale power generation system with the speed and torque control algorithm for the specified wind characteristics.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.57-64
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• 2013

The functional characteristic of LISN circuit, which is used for measurements of conductive noise in mains power line, is basically related to frequency characteristics of passive elements like inductors used in the circuit as well as the frequency response of inductors is highly related to the resins used in the varnishing process. The significant problem in determination of an inductor's frequency characteristic is the intrinsic resistance, inductance and parasitic capacitance. In this triplet, the parasitic capacitance is the major limiting factor of inductor's frequency range. This capacitance depends on inductor design parameters and materials filling the spaces of coil like resin and its coherency after curing process. In this paper, two similar inductors were designed and built. The first inductor was not varnished while the second one was varnished with VPI technology. VPI, or Vacuum, Pressure, Impregnation technology is one of the most reliable methods performing good insulating conditions for electrical circuits and windings based on resins. The measured results show that implying varnishing technology does not significantly affect the frequency response. However, due to mechanical solidity aspects and improved environmental protection, it is better to varnish the inductors.