• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.119-127
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• 2019

This paper proposes a new authentication model to solve the problem of personal information takeover and personal information theft by service providers using centralized servers for user authentication and management of personal information. The centralization issue is resolved by providing user authentication and information storage space through a decentralize platform, blockchain, and ensuring confidentiality of information through user-specific symmetric key encryption. The proposed model was implemented using the public-blockchain Ethereum and the web-based wallet extension MetaMask, and users access the Ethereum main network through the MetaMask on their browser and store their encrypted personal information in the Smart Contract. In the future, users will provide their personal information to the service provider through their Ethereum Account for the use of the new service, which will provide user authentication and personal information without subscription or a new authentication process. Service providers can reduce the costs of storing personal information and separate authentication methods, and prevent problems caused by personal information leakage.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.212-217
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• 2012

A fuzzy set $A$ defined on a probability space ${\Omega}$, $\mathfrak{F}$, $P$ is called a fuzzy event. Zadeh defines the probability of the fuzzy event $A$ using the probability $P$. We define the generalized triangular fuzzy set and apply the extended algebraic operations to these fuzzy sets. A generalized triangular fuzzy set is symmetric and may not have value 1. For two generalized triangular fuzzy sets $A$ and $B$, $A(+)B$ and $A(-)B$ become generalized trapezoidal fuzzy sets, but $A({\cdot})B$ and $A(/)B$ need not to be a generalized triangular fuzzy set or a generalized trapezoidal fuzzy set. We define the normal fuzzy probability on $\mathbb{R}$ using the normal distribution. And we calculate the normal fuzzy probability for generalized triangular fuzzy sets.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.193-200
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• 2013

Recently, network coding has been actively studied to increase the spectral efficiency of two-way relay wireless channels such as cellular systems as well as broadcasting systems. In this paper, we derive the average transmission capacity and the outage probability of a network coding system, which utilizes two-way data transmission via the best relay rather than multiple relays. Since the data unbalance between the forward and the reverse link in two-way communication systems exists, we include the asymmetric link as well as the symmetric link in the analysis. It is noticed that the space diversity gain increases as the increase of the number of relays. Also we obtain 11.4 dB signal-to-noise ratio (SNR) gain with 9 relays compared to that with single relay in symmetrical link at the given conditions. In asymmetrical links, we denotes that the outage probability is more sensitive to the number of relays rather than data unbalance between the links.

• Journal of Haehwa Medicine
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• v.19 no.1
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• pp.87-98
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• 2010

There are four kinds of diagnosis methods in oriental medicine, and viewing diagnosis(望診) is the most important method among them. There are two ways in viewing diagnosis. These are viewing shape(觀形) and inspecting color(察色). Viewing shape diagnosis includes observation on geometric curve that is made by prominence of bones or lump of flesh, and examination on symmetric disparity and balance of vertical length among three vertical section of face. Inspecting color is literally inspecting several specified region of face. By Viewing shape, we can learn about characteristic physical mechanism of individuals, and basic disposition of reaction from inside and outside infinite stimulations. On the other hand, by inspecting color, we can estimate the very present pathologic and physiologic status of the patient. the estimation is based on principle that inside body changes reveal some reflections on facial skin surface. When you diagnosis patients with inspecting color method, It is important to distinguish color delicately, and to know where to see and what to know from it. The most important and frequently mentioned regions are myong-dang(明堂), eyes(眼) and In-dang(印堂). Myong-dang(明堂) indicates nose. In-dang(印堂) indicates the space between eyebrows. Unlike myong-dang(印堂) and eyes, In-dang(印堂) is occasionally treated as a trivial region then others. But, from research on classical books of facial examination and consideration of it's locational meanings, we've learned In-dang(印堂) is very important in viewing diagnosis, because this region is crossing of the other two regions and this fact means this region expresses the spiritual status as well as physical status in one region.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.6
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• pp.719-730
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• 2007

This study presents a thin-walled space frame element based on the classical Timoshenko beam theory. The element is derived according to the assumed strain field in order to resolve the shear-locking phenomenon. The shape function is developed in accordance with the strain field which is assumed to be constant at a 2-noded straight frame element. In this study, the geometrically nonlinear analysis applies the Corotational procedure in order to evaluate unbalanced loads. The bowing effect is also considered faithfully. Two numerical examples are given; monosymmetric curved and nonsymmetric straight cantilever. When these example structures behave lateral-torsional bucking, the critical loads are obtained by this study and ABAQUS shell elements. Also, the post-buckling behavior is examined. The results give good agreement between this study and ABAQUS shell.

• The Journal of Korean Association of Computer Education
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• v.21 no.6
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• pp.39-47
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• 2018

This paper dealt with investigating the number of minimal spanning ladders originated from ladder game and their properties as well as the related computational thinking aspects. The author modified the filtering techniques to enhance Mathematica project where a new type of graph was generated based on the algorithm using a generator of firstly found minimal spanning graph by repeatedly applying independent ladder operator to a subsequence of ladder sequence. The newly produced YC graphs had recursive and hierarchical graph structures and showed the properties of edge-symmetric. As the computational complexity increased the author divided the whole search space into the each floor of the newly generated minimal spanning graphs for the (5, 10) YC graph and the higher (6, 15) YC graph. It turned out that the computational thinking capabilities such as data visualization, abstraction, and parallel computing with Mathematica contributed to enumerating the new YC graphs in order to investigate their structures and properties.

• International Journal of Advanced Culture Technology
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• v.7 no.1
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• pp.231-236
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• 2019

Background/Objectives: This paper proposes a dual mode feedback-controlled cycling system for children with spastic cerebral palsy to rehabilitate upper extremities. Repetitive upper limb exercise in this therapy aims to both reduce and analyze the abnormal torque patterns of arm movements in three- dimensional space. Methods/Statistical analysis: We designed an exercycle robot which consists of a BLDC motor, a torque sensor, a bevel gear and bearings. Mechanical structures are customized for children of age between 7~13 years old and induces reaching and pulling task in a symmetric circulation. The shafts and external frames were designed and printed using 3D printer. While the child performs active/passive exercise, angular position, angular velocity, and relative torque of the pedal shaft are measured and displayed in real time. Findings: Experiment was designed to observe the features of a cerebral palsy child's exercise. Two children with bilateral spastic cerebral palsy participated in the experiment and conducted an active exercise at normal speed for 3 sets, 15 seconds for each. As the pedal reached 90 degrees and 270 degrees, the subject showed minimum torque, in which the child showed difficulty in the pulling task of the cycle. The passive exercise assisted the child to maintain a relatively constant torque while visually observing the movement patterns. Using two types of exercise enabled the child to overcome the abnormal torque measured in the active data by performing the passive exercise. Thus, this system has advantage not only in allowing the child to perform the difficult task, which may contribute in improving the muscle strength and endurance and reducing the spasticity but also provide customizable system according to the child's motion characteristic. Improvements/Applications: Further study is needed to observe how passive exercise influences the movement characteristics of an active motion and how customized experiment settings can optimize the effect of pediatric rehabilitation for spastic cerebral palsy.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.5
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• pp.65-72
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• 2021

700 W class laboratory model Hall thruster, which can be used for the orbit control or station keeping of small satellites, was developed. The size of the discharge channel was determined using a scaling law, and the magnetic field was designed to be symmetric with respect to the midline of the discharge channel and to be maximized outside the discharge channel. Base pressure of a vacuum chamber was maintained below 2.0×10^-5 Torr during experiments, and the thrust was measured by a thrust stand. The anode flow rate and coil current were varied with the fixed anode voltage at 300 V. Under the operation condition at 2.36 mg/s anode flow rate and 2.4 A coil current, performance was optimized as 38 mN thrust, 1,540 s total specific impulse, and 50 % anode efficiency at 620 W anode power.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.119-128
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• 2008

In the case of a circular shaft, it is expected that asymmetric loads should apply on the surface rather than symmetric loads due to geographical factors and the non-homogeneity of the jointed rock masses. In this study, discontinuous numerical analysis was carried in order to analyze the characteristics of asymmetric load distribution on the wall of the circular shaft due to anisotropy caused by heterogeneity of rock masses affected by the discontinuities like as a Joint. And it was also analyzed that the effect of the mechanical properties varied with the rock mass rating and horizontal stress with depth had influence in the asymmetric load on the wall of the shaft. In the case of considering the effect of the joint as variable, asymmetric load ratio $(R_p)$, which was defined as the ratio of the load subtracted minimum from maximum to minimum, was below 25% in the hard rock. As regarding the variation of the rock mass rating with depth as variable, the value of $R_p$ was below than 25% in the hard rock, and the value between 30% and 40% in the soft rock. On the other hand, the $R_p$ of fractures rock was between $45{\sim}50%$ which value was much higher than that in better rock mass rating.

• Journal of Astronomy and Space Sciences
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• v.19 no.2
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• pp.123-132
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• 2002

The electron density and temperature in the topside ionosphere are observed by the ionosphere Measurement Sensor (IMS) onboard the KOMPSAT-1, which has the sun-synchronous orbit of the altitude of 685 km and the orbital inclination of $98^{\circ}$ with a descending node at 22:50LT. Observations have been analyzed to determine the seasonal variations of the electron density and temperature in the low-latitude region. Only the night-time (22:50LT) behavior on magnetically quiet days (Kp < 4) has been examined. Observations show a strong longitudinal and seasonal variation. Generally, in the dip equator the density increases and the temperature decreases. In equinox the latitudinal distributions of the electron density and temperature are quite symmetric about the dip equator. However, the local maximum of the density and the local minimum of the temperature shift toward the Northern hemisphere in summer solstice but the Southern hemisphere in winter solstice. Such variations are due to the influences of field-aligned plasma transport induced by F region neutral wind. Compared with the IRI95 model, the observed electron density and temperature show significant differences from those predicted by the IRI95 model.