• Archives of design research
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• v.17 no.1
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• pp.179-190
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• 2004

The human effort to make personal privacy and safety from outer environment has brought the improvement of security system through the technological development. Especially as a apartment dwelling and lifestyle is general, the role and function of door lock system is more important than ever. The research for user-centered approach and design on the door lock system should be implemented under the circumstances. This study has focused on the development of making safety as well as easy interface to design door lock system. The price also is competitive as compared with other door lock products. The goal of this study is to propose the alternatives not only to develop door lock design but also to search the innovative way of locking system design.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.86-88
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• 2017

The digital door lock is an electronic door lock that uses a password system and has the function of automatically locking the door when the door is closed, thus eliminating the worry about the door lock. As the technology has gradually developed, various authentication technologies such as semiconductor key system, RFID, and fingerprint recognition have been introduced. However, there is a danger of copying the door lock key, and there are password stealing and infringement. In this paper, we develop a remote control system that can unlock or open a smartphone to supplement the user's risk. The system you are going to develop can use WiFi to check if the door is locked or open on your smartphone, and you can lock or unlock the door remotely.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.255-258
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• 2003

The hysteresis characteristics of flux-lock reactor, which is an essential component of flux-lock type superconducting fault current limiter (SFCL), was investigated. The hysteresis loss of iron core in flux-lock type SFCL does not happen due to its winding's structure especially in the normal state. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. Through the hysteresis curves together with the fault current level due to the inductance ratio for the 1st and 2nd winding, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.849-855
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• 2010

This paper investigated the roll lock-in phenomena of a canard-controlled missile with freely spinning tailfins by applying Falanga's roll-rate equation. To confirm and validate the accuracy of the results of the roll-rate and roll lock-in prediction for freely spinning tailfins, the results were compared with Blair's wind tunnel test data. For calculation of the roll-rate of freely spinning tailfins, rolling moment coefficients of the tailfins were obtained from the wind tunnel test data and roll-damping coefficients were calculated by missile DATCOM. The roll-rate and roll lock-in of the freely spinning tailfins were calculated by applying these values to the roll-rate equation for freely spinning tailfins. The calculation results showed good agreement with the wind tunnel test data, and the roll lock-in could be anticipated as well.

• Journal of Navigation and Port Research
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• v.26 no.2
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• pp.177-182
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• 2002

In inner harbour of Incheon port, there are two lock gates (50KT, 10KT) which have two gates per lock gate in inner/outer sides except a gate in inner harbour side of 10KT. Due to the lack of the fore-mentioned gate, the use of 10KT lock gate is suspended in energy 3 years for regular maintenance. Now an additional gate is under construction in order to improve the efficiency of the 10KT lock gate. This paper will be aimed to evaluate the operational utilization levels of lock gates in present and future. The operational utilization levels of lock gates in 1998 are evaluated 0.2119 in 10KT lock gate, 0.2061 in 50KT lock gate which were considered the 46.5 closed days every 3 years for 10KT regular maintenance. The levels are estimated to 0.2246(10KT), 0.2539(50KT0 in 2006 and 0.2241(10KT), 0.2560(50KT) in 2011. The levels of 50KT lock gate in 2011 are evaluated to be more rapidly increased up to 24.5% from the levels in 1998.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.3
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• pp.275-282
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• 2009

Generally, the sinusoidal cavity dither is adopted to ring laser gyroscope for eliminating the lock-in which is non-linear effect at the small rotation input. Despite this method, there are some remained errors which are generated at the dither turnaround, and those errors produce random walk which is a general character of a ring laser gyroscope. As one of the numerous research results for compensating these errors, there is a special lock-in compensation method which is the method of error estimation and compensation by comparing the beat signal periods of before and after the dither turnarounds. In this paper, by ring laser gyroscope modeling and numerical analysis, we verified the theoretical validity and confirmed the effectiveness of this method in expectation of the possible beat signal measurement time resolution. As a result, we confirmed the random walk decreases from a-half to a-third by this lock-in compensation method. So, it is expected to be a remarkable method for reducing the INS alignment time.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.3
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• pp.132-142
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• 2019

Purpose: The purpose of this finite element analysis study is to introduce the novel Lock screw system and analyze its mechanical property to see if it can prevent abutment screw loosening. Materials and Methods: The Lock screw is a component tightened on the inside of the implant abutment which applies compressive force to the abutment screw head. To investigate the effect, modeling was done using CAD program and it was analyzed by finite element analysis under various load conditions. First, the preload was measured according to the tightening torque of the abutment screw then it was compared with the theoretical value to verify the analytical model. The validated analytical model was then divided into those with no external load and those with 178 N, and the tightening torque of the lock screw was changed to 10, 20, 30 Ncm respectively to examine the property of stress distribution on the implant components. Results: Using Lock screw under various loading conditions did not produce equivalent stresses beyond the yield strength of the implant components. In addition, the axial load was increased at the abutment-abutment screw interface. Conclusion: The use of Lock screw does not exert excessive stress on the implant components and may increase the frictional force between the abutment-abutment screw interface, thus it is considered to prevent loosening of the abutment screw.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.317-322
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• 2013

This paper presents a new laser lock-in thermography (LLT) technique for nondestructive evaluation. LLT utilizes a modulated continuous wave laser beam as a heat source to obtain high fidelity thermal wave images even at the presence of background heat disturbances. The thermal waves propagating along the surface and through-the-thickness directions of a structure are visualized using newly developed laser lock-in amplitude and phase images, enhancing the detectability of surface and subsurface defects. The LLT technique is numerically investigated and experimentally validated using thermal images obtained from a steel specimen with low emissivity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.1
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• pp.37-41
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• 2017

In this paper, the fault current limiting characteristics of the flux-lock type SFCL (superconducting fault current limiter) using magnetic application circuit were analyzed. The flux-lock type SFCL has the structure to install the magnetic application circuit, which can increase the resistance of HTSC ($high-T_C$ superconducting element comprising) the SFCL. To analyze the fault current limiting effect of the flux-lock type SFCL through the magnetic flux application circuit, the flux-lock type SFCL either with the magnetic flux circuit or without the magnetic flux circuit was constructed and the fault current limiting characteristics of the SFCL were compared each other through the short-circuit tests.

• Journal of Information Technology Services
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• v.13 no.3
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• pp.323-331
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• 2014

This research is based on real-time service model that uses lock screen of smart devices which is mostly exposed to device users. The potential for lock screen space is immense due to their exposing time for user. The effect can be maximized by offering useful information contents on lock screen. This service model offers real-time keyword with abridged sentence. They match real-time keyword with news by using text matching algorithm and extracts kernel sentence from news to provide short sentence to user. News from the lock screen to match real-time query sentence, and then only to the original core of the ability to move a user evaluation was conducted after adding. The report provided a key statement users feel the lack of original Not if you go to an average of 5.71%. Most algorithms allow only real-time zoom key sentence extracted keywords can accurately determine the reason for that was confirmed.