• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.63-70
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• 2009

Recently, in the security token based authentication system, there is an increasing trend of using fingerprint for the token holder verification, instead of passwords. However, the security of the fingerprint data is particularly important as the possible compromise of the data will be permanent. In this paper, we propose an approach for secure fingerprint verification by distributing both the secret and the computation based on the fuzzy vault(a cryptographic construct which has been proposed for crypto-biometric systems). That is, a user fingerprint template which is applied to the fuzzy vault is divided into two parts, and each part is stored into a security token and a server, respectively. At distributing the fingerprint template, we consider both the security level and the verification accuracy. Then, the geometric hashing technique is applied to solve the fingerprint alignment problem, and this computation is also distributed over the combination of the security token and the server in the form of the challenge-response. Finally, the polynomial can be reconstructed from the accumulated real points from both the security token and the server. Based on the experimental results, we confirm that our proposed approach can perform the fuzzy vault-based fingerprint verification more securely on a combination of a security token and a server without significant degradation of the verification accuracy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.59-69
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• 2009

RFID tag search system which is used to find a specific tag has an application such as asset management, supply chain, and this search scheme has been given much attention so far. In RFID tag search system, especially, mobility of the reader is important in order to search tags. Therefore, even though the handheld reader cannot connect with the central database because of unreliable wireless connection or remote location, handheld reader should search the specific tag without help of the central database. In addition, in RFID tag search system, users hold not the tag but the reader, the privacy of users should be considered. Since the signal strength of the reader is stronger than that of the tag, the privacy of the reader holder is very important. Recently, in order to solve these problems, a number of RFID tag search schemes have been proposed. However, since these schemes did not consider the privacy of reader holders, there are serious privacy breaches of reader holders. In this paper, we propose efficient RFID tag search protocol for passive tags. Our proposed scheme preserves the privacy of reader holders.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.6
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• pp.63-71
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• 2006

In this paper, we propose a secure solution for user authentication by using fingerprint verification on the sensor-client-server model, even with the client that is not necessarily trusted by the sensor holder or the server. To protect possible attacks launched at the untrusted client, our solution makes the fingerprint sensor validate the result computed by the client for the feature extraction. However, the validation should be simple so that the resource-constrained fingerprint sensor can validate it in real-time. To solve this problem, we separate the feature extraction into binarization and minutiae extraction, and assign the time-consuming binarization to the client. After receiving the result of binarization from the client, the sensor conducts a simple validation to check the result, performs the minutiae extraction with the received binary image from the client, and then sends the extracted minutiae to the server. Based on the experimental results, the proposed solution for fingerprint verification can be performed on the sensor-client-server model securely and in real-time with the aid of an untrusted client.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.542-549
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• 2022

Purpose: Pipes are widely used as applied devices in many industrial fields such as machinery, electronics, electricity, and plants, and are also widely used in safety-related fields such as firefighting and chemistry. With the diversification of products, the importance of technology in the piping field is also increasing. In particular, when changing the existing copper pipe to stainless steel, it is necessary to evaluate safety and flow characteristics through structural analysis or flow analysis. Method: This study investigated the structural stability of the 6.35 and 15.88 socket models, which are integrated insert type connectors developed by a company, using FEM. For structural analysis, HyperMesh as pre-processor, HYPER VIEW as post-processor, and LS-DYNA as solver were used. Result: In the case of 6.35 socket, the maximum stresses at hook, holder and hinge were 95.02MPa, 19.59MPa and 44.01MPa, respectively, and in case of 15.88 socket, it was 127.7 MPa, 40.09MPa and 45.23MPa, respectively. Conclusion: Comparing the stress distribution of the two socket models, the stress in the 15.88 socket, which has a relatively large outer diameter, appears to be large overall, but it is significantly lower than the yield stress of each material, indicating that there is no problem in structural safety in both models.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.243-253
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• 2019

Geyonggi-geommu have developed based on the long history of Korean sword dance. Han Sung-joon, the great master of modern music and dance of Korea during the Japanese colonial period, collected and reconstructed folk dances that had disappeared or were cut off due to the policy to obliterate Korean culture through Chosun Music Dance Research Society. Since then, it has been passed down to Kang Sun-young and Kim Geun-hee that has designated as the Intangible Cultural Property No. 53. of Geyonggi-do in 2011. This study focuses on highlighting the uniqueness of Geyonggi-geommu for proper modeling and transmission of Geyonggi-geommu with historical significance so as to understand and preserve the Intangible Cultural Heritage. This study examines the transmission system of Geyonggi-geommu, followed by Kang Sun-young and Kim Geun-hee, originated by the master Han Sung-Joon of Geyonggi-geommu. Geyonggi-geommu has its uniqueness of using the pure Korean dance terminology established by the holder Kim Geun-hee at the time of designation of intangible cultural properties in Gyeonggi-do. The unique features of Geyonggi-geommu are performed and transmitted in two forms, Daemu(Group dance) and Holchum(Solo dance) which are not currently found in other regions. This is meaningful to passed down according to the original form of Geommu(Sword dance). In particular, the Holchum(Solo dance) is a form of artistic dance, showing the beauty of the sword dance during the Chosun Dynasty. In short, Gyeonggi-geommu can be described as an artistic dance with a soft and strong temperament considering its unique features.

• Analytical Science and Technology
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• v.19 no.3
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• pp.255-262
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• 2006

In this study, we attempted to evaluate the sorptive loss of VOC upon their contact with different material surfaces including clothing pieces. For the purpose of this study, we developed a method to evaluate such loss by employing a filter holder pack in the thermal desorption line of the GC/FID system. The calibration curves of different aromatic VOCs including benzene, toluene, and xylene were made by loading them at different quantities through the analytical line. A series of experiments were conducted repetitively to draw calibration data sets for all three materials covering glass fiber, cotton, and nylon. The results were then compared in terms of both material types and of VOC types. The extent of sorptive loss increased in a highly systematic manner across different materials such as glass fiber, cotton, and nylon. The patterns of sorptive loss also increased gradually across VOC type such toward in the direction of increasing molecular weights: benzene, toluene, and xylene. According to this experimental study, it is concluded that sorptive behavior of pollutint compounds like VOC can be controlled by the combined effects of both chemical properties and material characteristics.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.39-48
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• 2024

A car horn serves a crucial safety role as a means of communication between drivers and a part that alerts pedestrians in advance. While previous studies have utilized finite element method and electric circuit model to simulate and analyze characteristics of the car horns, there remains a lack of research on design methods of a trumpet horn. This paper presents a design approach that predicts the operating frequency based on the acoustic reactance at the throat of the horn, once the vibrating part is determined. We deal with a horn combining both an exponential horn and a waveguide in the acoustic section, and confirm that the acoustic reactance at the horn throat measured by impedance tube experiment agrees well compared with the numerical result obtained using the finite element method. The resonance frequency of the car horn is predicted using the COMSOL Multiphysics finite element numerical analysis model, and the proposed design method is validated by measuring the operating frequency of the designed horn in a sound pressure experiment. As a result, the resonance measured in a semi-anechoic chamber environment by applying a DC voltage of 12 [V] excluding the holder occurs accurately within a few [Hz] of the design operating frequency. This paper discuss the design method of a trumpet horn from the perspective of the horn's acoustic reactance, and is expected to be useful for designing horn systems.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.315-322
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• 2013

Purpose: To evaluate the axial displacement of implant-abutment assembly after cyclic loading in internal tapered connection system. Materials and methods: External butt-joint connection implant and internal tapered connection implant were connected with three types of abutment for cement-retained prostheses, i.e. external type abutment (Ext group), internal tapered 1-piece abutment (Int-1 group), and internal tapered 2-piece abutment (Int-2 group). For each group, 7 implants and abutments were used. The implantabutments assemblies were clamped into the implant holder for vertical loads. A dynamic cyclic loading was applied for $150{\pm}10N$ at a frequency of 4 Hz. The amount of axial displacement of the abutment into the implant was calculated at each cycle of 0, 5, 10, 50, 100, 1,000, 5,000, and 10,000. A repeated measures analysis of variance (ANOVA) for the overall effect of cyclic loading and the pattern analysis by linear mixed model were used for statistical analysis. Differences at P<.05 were considered statistically significant. Results: The mean axial displacement after 10,000 cycles were $0.714{\pm}0.488{\mu}m$ in Ext group, $5.286{\pm}1.604{\mu}m$ in Int-1 group, and $11.429{\pm}1.902{\mu}m$ in Int-2 group. In the pattern analysis, Int-1 and Int-2 group showed continuous axial displacement at 10,000 cycles. There was no declining pattern of axial displacement in the Ext group. Conclusion: The pattern of linear mixed model in Ext group showed no axial displacement. There were continuous axial displacements in abutment-implant assemblies in the Int-1 and Int-2 group at 10,000 cycles. More axial displacement was found in Int-2 group than in Int-1 group.

• Journal of Korean Academy of Nursing
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• v.26 no.4
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• pp.946-962
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• 1996

The purpose of this study was to contribute to the development of clinical instruction by students' ratings of teaching effectiveness in clinical nursing education. The subjects were comprised of graduating class 618 students from 24 nursing colleges in the nation. The instruments used in this study were "general characteristics & status of clinical nursing education" developed by the researcher and "Instrument to Measure Effectiveness of Clinical Instructors" by Reeve(1994). The 50 questions used in the questionaire were categorized into 13 components subject to factor analysis. The 13 components were interpersonal relationships, communication skills, role model, resource for students, favorable to students, encouraging to think for selves, teaching methods, evaluation, finding assignments for objectives, organization of subject matter, professional competence, knowledge of subject matter & working with agency personnel. The results of this study are as follows 1. Status of clinical nursing educaion : 1) Clinical nursing education were led by nursing professors(44.9%), a team of both nuring professor & head nurse(6.8%), instructors from specific hospital(15.1%), instuctos for a specific subject(14.6%), & head nurse(6.8%). For 3-year program students, 34.6% of the clinical nursing education were led by instructors from specific hospital & 51.4% of the education by nursing professors for Bachelor's program. 2) The contents for clinical education comprised of Conference being the most frequent of 34.5% ; a combination of Nursing skills, Orientation, Conference etc.22.0% : Nursing process 21.7% : Orientation 13.5% : Inspection(making rounds ) 6.4%, & Nursing skills of 2% being the least frequent. 3) Students' preference of clinical teachers from the highest to the lowest were instructors for a specific subject being the most desired (44.9%) followed by nursing professor, head nurse, a team of both nursing professor & head nurse, & instructors from specific hospital being the least desired. 4) Students felt that the qualification for clinical teachers should be at least a master's degree holder and 5 or more years of clinical experience. The reason they felt was because knowledge & experience are imperative for professional education. 2. Clinical teaching effectiveness : The total points for teaching effectiveness was 147.97(mean of 2.95±0.98) where the total score is considered to be an average rating. 3. Teaching effectiveness as status of clinical nursing education : 1) The score ratings for the clinical instructors from the highest to the lowest were as follows : instructors for a specific subject, instructors from specific hospitals, a team of both nursing professors & head nurses, nursing professors, head nurses, which resulted in significunt difference(F=4.53, P<0.001). 2) The rating scores based on the teaching program from the highest to the lowest were as follws ; nursing skills, nursing process, a combination of nursing skills, orientation, conference etc. , conferences, orientation, inspection, which resulted in significunt difference(F=10.97, P<0.001). 4. Based on 13 categorized components from the questionaires, questions related to communication skills scored the highest points of 3.20 where inquiries regarding resource for students scored the lowest points of 2.38. 5. Among the 13 categorial components from the questionaire, Interpersonal relationship, Communication skills, Resource for students, Encouraging to think for selves, Evaluation, Teaching method, Finding assignment for objectives, Organization of subject matter, Professional competence, & Working with agency personnel, instructors for a specific subject scored the highest points and head nurse scored the lowest, which resulted in significant difference. Favorable for students, instructors for a specific subject scored highest points and nursing professor scored the lowest, which resulted in significant deference (F=5.39, P<0.001). Role model & Professional competence, instructors for a specific subject scored the highest points and head nurse scored the lowest, with minimum variation(F=1.29, P>0.05 : F=1.64, P>0.05) 6. Based on 13 categorial components as a whole, the highest points scored among the 5 groups of clinical teachers was instructors for a specific subject and the lowest, by head nurse(F=1.94, P<0. 001). A team of both nursing professor & head nurse attained higher score in clinical education than their independent education.

• Journal of Animal Environmental Science
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• v.13 no.2
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• pp.113-120
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• 2007

This study was conducted to measure Nitrogen(N), Phosphate($P_2O_5$), Potassium ($K_2O$), Organic matter(OM) and Moisture content of liquid pig manure by Near Infrared Spectroscopy(NIRS) and to develop an alternative and analytical instrument which are used for measurement of N, $P_2O_5$, $K_2O$, OM, and Moisture contents for liquid pig manure. The liquid pig manure sample's transmittance spectra were measured with a NIRS in the wavelength range of 400 to 2,500 nm. Multiple linear regression and partial least square regression were used for calibrations. The correlation coefficient(RSQ) and standard error of calibration(SEC) obtained for nitrogen were 0.9190 and 2.1649, respectively. The RSQ for phosphate, potassium, organic matter and moisture contents were 0.9749, 0.5046, 0.9883 and 0.9777, and the SEC were 0.5019, 1.9252, 0.1180 and 0.0789, respectively. These results are indications of the rapid determination of components of liquid pig manure through the NIR analysis. The simple analytical instrument for liquid pig manure consisted of a tungsten halogen lamp for light source, a sample holder, a quartz cell, a SM 301 spectrometer for spectrum analyzer, a power supply, an electronics, a computer and a software. Results showed that the simple analytical instrument that was developed can approximately predict the phosphate, organic matter and moisture content of the liquid pig manure when compared to the analysis taken by NIRS. The low predictability value of potassium however, needs further investigation. Generally, the experiment proved that the simple analytical instrument was reliable, feasible and practical for analyzing liquid pig manure.