• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.81-86
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• 2009

Almost all network systems provide an authentication mechanism based on user ID and password. In such system, it is easy to obtain the user password using a sniffer program with illegal eavesdropping. The one-time password and challenge-response method are useful authentication schemes that protect the user passwords against eavesdropping. In client/server environments, the one-time password scheme using time is especially useful because it solves the synchronization problem. In this paper, we propose a new identification scheme One Pass Identification. The security of Password base System is based on the square root problem, and Password base System is secure against the well known attacks including pre-play attack, off-line dictionary attack and server comprise. A number of pass of Password base System is one, and Password base System processes the password and does not need the key. We think that Password base System is excellent for the consuming time to verify the prover.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.3
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• pp.216-223
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• 2005

A computer clock has limits in accuracy and precision affected by its inherent instability, the environment elements, the modification of users, and errors of the system. So the computer clock needs to be synchronized with a standard clock if the computer system requires the precise time processing. The purpose of synchronizing clocks is to provide a global time base throughout a distributed system. Once this time base exists, transactions among members of distributed system can be controlled based on time. This paper discusses the integrated approach to clock synchronization. An embedded system is considered for time synchronization based on the GPS(Global Positioning System) referenced time distribution model. The system uses GPS as standard reference time source and offers UTC(Universal Time Coordinated) through NTP(Network Time Protocol). A clock model is designed and adapted to keep stable time and to provide accurate standard time with precise resolution. Private MIB(Management Information Base) is defined for network management. Implementation results and performance analysis are also presented.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.185-190
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• 2007

This article describes a development CDMA LBS in order to apply to "Control System of Underground Infrastructure Fire Accident" which one of U-City Projects of Seoul City. Our goal guides taking shelter of the sufferer it will not be able to use a GPS when the fire occurs from subway station. There are Location measurement methods which measures the AOA(Angle of Arrival) of the signal which it sends with the MS(Mobile station) from the BS(Base station), an electronic delivery time (TOA:Time of Arrival) and the relative difference of electronic arrival time from Base stations (TDOA:Time Difference of Arrival). This time the error due to a multiplex course error and near-far problem and NLOS(Non Line of Sight). We are planning to construct the Test Bed which is an error below 1 meter.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.86-91
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• 2022

The mechanical structures mounted on vehicles or aircrafts are subject to random accelerations, such as earthquakes, at the base, and their responses have been calculated through spectrum analysis. However, this method poses a challenge during the synthesis of the responses owing to the loss of the vibration phase. It is necessary to evaluate the time history results to obtain the exact responses; therefore, an efficient technique is proposed to solve this issue. The present technique involves constructing a superelement using the sub-structuring method and finding solutions for this superelement. The finite element model (FEM) was substituted by a superelement, which was simplified into one element with selected nodes. Comparing the numerical results of the superelement with the time history responses for the original finite element model, the two solutions agree well despite the fact that the computation time of the proposed technique has been greatly shortened.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.04a
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• pp.113-118
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• 1986

Nowdays switching software designs are based on the concept of maximizing efficiency. This idea is to put through the most call, in the fastest time, using the fewest possible resources. So the memory usages are embossed one of the most important part to be considered in the switching software. This paper discusses the general concepts of switching software at first, then describes the switching data base from the view point of the access time, memory efficiency, and call processing environment.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.47-56
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• 1998

Designing Trim die block is a complicated and time-consuming process heavily resting on the experience of the designer. To reduce design time and human errors, a knowledge base is used to automated the design process. In this paper, a framework of the Rule-based CAD System is presented for trim die block design consisting of a rule-base, design process control module and geometric modeler (CATIA). The rule-base includes design rules and know-how of design specialist. CATIA is used as the overall CAD environment and rule-base and design control modules are developed by C++ language with an interface to CATIA. Using the rule-base, the designer can explore alternating designs fast by changing design parameters and the part-list is automatically created which avoids miscommunication.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.615-619
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• 2009

(+)-$Tr{\ddot{o}}ger$'s base in $Tr{\ddot{o}}ger$'s base racemates that inhibits thromboxane A2($T{\times}A2$) synthase has been used to treat arteriosclerosis. Separation of (+)-$Tr{\ddot{o}}ger$'s base by chromatography has become a major concern. However separation experiments of (+)-$Tr{\ddot{o}}ger$'s base need time and consumables so that simulation with Aspen Chromatography could save time and costs by predicting the efficiency of separation. Injection amount and eluent flow rate were varied to compare the resolutions and yields of TB(-) and TB(+). Highest resolution and yield were attained at the eluent rate of 0.25 mL/min. Isotherms representing the relationship between mobile phase concentration and stationary phase concentration were changed to get the best separation with Ideal Adsorbed Solution(IAS) Statistical Lanmuir isotherms.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.4
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• pp.493-502
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• 2003

Statement of problem : Removable partial denture and complete denture often require denture base relines to improve the fittness against tissue-bearing mucosa because of the gradual change in edentulous ridge contour and resorption of underlyng bony structure. Self-curing hard reline resins offers the immediate and relatively inexpensive means to be recondition the surface of denture base directly However weak bond between denture base resin and reline material can harbor bacteria, promote staining, or result in complete separation of the two materials. Purpose : The purpose of this study was to evaluate the effect of denture cleansers on bond strength and surface hardness of reline resin to denture base resin Denture base resin beams($60.0{\times}15.0{\times}3.0mm$) were made with Lucitone 199. Material and methods : 10mm section was removed from the center of each specimen. The samples were replaced in the molds and the space of l0mm sections were packed with Tokuso Rebase reline material. The specimens were immersed in denture cleansers (Polident, Cleadent) and were evaluated after 1 week, 2 weeks, and 4 weeks. The bond strength and surface hardness of self-curing hard reline materials to heat-curing denture base resin were measured using an UTM (universal testing machine). Results and conclusion : 1) There was no significant difference of usage, kind, and denture cleaner by application time on the bonding strength of self-curing hard reline resin to denture base resin. 2) There was no significant difference of usage, kind, and denture cleaner by application time on the surface hardness, but the surface hardness showed decreasing tendency, as the time of immersion was extended. 3) The failure modes of the specimens was initially adhesive failure and finally cohesive failure of self-curing hard reline resin.

• Earthquakes and Structures
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• v.12 no.1
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• pp.35-45
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• 2017

The current paper investigates the effect of the seismic pounding of neighboring buildings on the response of structures isolated by Triple Friction Pendulum Bearing (TFPB). To this end, a symmetric three-dimensional single story building is modeled for analysis with two specified levels of top deck and base deck, to capture the seismic response of the base isolators and building's roof. Linear elastic springs with different level of gaps are employed to calculate the impact between the buildings. Nonlinear Dynamic Time History Analyses (NDTHA) are conducted for seismic evaluation. Also, five different sizes with four different sets of friction coefficients are assumed for base isolators to cover a whole range of base isolation systems with various geometry configurations and fundamental period. The results are investigated in terms of base shear, buildings' drift and top deck acceleration of the superstructure. The results also indicate the profound effect of the stiffness of the adjacent buildings on the value of the impact they impose to the superstructure. Also, in situations of potential pounding, the increment of the fundamental period of the TFPB base isolator could intensify the impact force up to nearly five-fold.

• The Journal of Information Systems
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• v.3
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• pp.71-82
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• 1994

Knowledge acquisition, maintenance of knowledge base, and validation and verification of knowledge are the addressed bottlenecks of building successful knowledge based systems. Along with the increment of interesting in the knowledge based systems, the organization needs to develop a new one although it has a similar one. This causes several serious problems including knowledge redundancy and maintenance of knowledge base. This paper present three models of the reusable knowledge base which might be the solution to the above problem. Three models are : 1) multiple knowledge bases for a single AI application, 2) multiple knowledge bases for multiple AI applications, 3) a single knowledge base for multiple AI applications. A new approach to build such a reusable knowledge base in a homogeneous environment is presented. Our model combines the essential object-oriented techniques with rules in a consistent manner. Important aspects of applying object-oriented techniques to AI are discussed (inheritance, encapsulation, message passing), and some potential problems in building an AI application (decomposition technique of knowledge, search time, and heterogeneous environment) are pointed out. The models of a reusable knowledge base provide several amenities : 1) reduce the knowledge redundancy, 2) reduce the effort of maintenance of the knowledge base, 3) reuse the resource of the multiple domain knowledge bases, 4) reduce the development time.