• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.42-46
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• 2013

In 2010, Airworthiness standard for VLA(Very Light Airplane) category was newly introduced as KAS Part VLA. KAS Part VLA is an adaption of EASA CS-VLA which was developed to reduce unnecessary burden of manufacturer of very light, simple, single-reciprocating-engine/propeller powered airplanes having low stall speeds by tailoring some requirements of Part 23. In this paper, difference and similarity of structural requirements between Part 23 and VLA was analyzed.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.152-154
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• 1997

This paper describes a study of a stabilisation scheme of a stepping motor in the driving systems of the Fiber Optic Gyrocompass absolutely required a constant speed and a precise position control with fine step angle. The new stabilisation scheme combining microstepping control and frequency modulation is developed which enables the experimental machine to be capable of stable running to a stepping frequency in the range 5 times the open-loop stall frequency.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.513-515
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• 2008

Due to the rapid development of telecommunication industry, most telecom operators are investing to upgrade their access networks by using optical cables instead of copper cables. Building new telecom ducts for optical cable installation requires so huge capital expenses that most telecom operators need to remove unused copper cables in order to secure enough space to in-stall optical cables. In this paper, we will present a alternative method to extract copper from removed copper cables.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.3
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• pp.1074-1082
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• 1996

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.6 s.360
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• pp.42-49
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• 2007

CABAC(Context-based Adaptive Binary Arithmetic Coding) among various entropy coding schemes which are used to improve compression efficiency in H.264/AVC has a high hardware complexity and the fast calculation is difficult because data dependancy exists in the bit-serial process. In this paper, the proposed architecture efficiently compose the renormalization process of binary arithmetic encoder which is an important part of CABAC used in H.264/AVC. At every clock cycle, the input symbol is encoded regardless of the iteration of the renormalization process for every input symbol. Also, the proposed architecture can deal with the bitsOutstanding up to 127 which is adopted to handle the carry generation problem and encode input symbol without stall. The proposed architecture with three-stage pipeline has been synthesized using the 0.18um Dongbu-Anam standard cell library and can be operated at 290MHz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.692-697
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• 2005

A canard type aircraft, which has good wing stall and stall/spin proof characteristics, is being developed. The previous first and second prototypes, having full depth core sandwich type wing and fixed landing gear, was built for test flights. Newly developing Firefly will be equipped with retractable landing gear and conventional foam core sandwich laminate for wing and fuselage. For manufacturing, composite material process has been studied including coupon tests. Wet lay-up onto foam core with glass fabric using lay-up mold has been chosen, and composite material parts are cured under room temperature and atmospheric pressure condition. In general, molded parts show so good surface smoothness and standardized quality that are best in mass production. In this study, we present the mold technology and development status for small aircraft firefly.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.90-98
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• 2010

This study intends to understand the change of the library's bookshelves shape, composition and arrangement based on the social-culture in each period. For this purpose, this study analyzes the morphological shift of the library's bookshelves and knowledge information focused on the history of western libraries from the ancient libraries to the modern public libraries before the 20th century. And the results are follows. 1) We can make sure that the changes of the library's bookshelves are based on the environmental factors like social cultural political factors and also understand that the knowledge information are developed based on the function which is decided by the needs of the times and the serious necessities of users. With this reason, the morphology and the function of the library's bookshelves have been changed. 2) The characters and meanings of the library's bookshelves are changed with the times from movable type to fixed type, from closing type to opening type, from privileged use to public use, from religious contents to general scientific contents. 3) The morphology of the library's bookshelves are shifted from cylindrical box to Chest type Press type and Lectern system, Stall system, Wall system and advanced to Mixed(Stall+Wall) system. 4) The construction and arrangement methods of the library's bookshelves are determined by the convenience and efficiency of the installation for the perusal environments as well as the regarding to the social-cultural factors. The arrangement criteria are determined by the security topics in the earlier stage, after that determined by the lightening topics and nowadays the access topics to the information. These analysis results are very useful to research the technology of the library's bookshelves to be changed continuously and also to forecast the morphology of the library's bookshelves can be planned in the spaces of the future libraries.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1355-1362
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• 2011

This paper describes a multi-mode LDPC decoder which supports three block lengths(648, 1296, 1944) and four code rates(1/2, 2/3, 3/4, 5/6) of IEEE 802.11n WLAN standard. Our LDPC decoder adopts a block-serial architecture based on min-sum algorithm and layered decoding scheme. A novel way to store check-node values and parity check matrix reduces the sizes of check-node memory and H-ROM. An efficient scheme for check-node memory addressing is used to achieve stall-free read/write operations. The designed LDPC decoder is verified by FPGA implementation, and synthesized with a $0.18-{\mu}m$ CMOS cell library. It has 219,100 gates and 45,036 bits RAM, and the estimated throughput is about 164~212 Mbps at 50 MHz@2.5v.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.8
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• pp.649-656
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• 2013

High-lift devices have a major influence on takeoff, landing and stall performance of an aircraft. Therefore, a slotted flap design optimization process is proposed in this paper to obtain the most effective flap configuration from supported 2D flap configuration. Flap deflection, Gap and Overlap are considered as main contributors to flap lift increment. ANSYS Fluent 13.0.0$^{(R)}$ is used as aerodynamic analysis software that provides accurate solution at given flight conditions. Optimum configuration is obtained by Sequential Quadratic Programing (SQP) algorithm. Performance of the aircraft with optimized flap is estimated using Aircraft Design Synthesis Program (ADSP), the in-house performance analysis code. Obtained parameters such as takeoff, landing distance and stall speed met KAS-VLA airworthiness requirements.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.609-617
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• 2014

Even though the variable pitch control of a wind turbine blade is known as an effective component for power control over the rated wind speed, it has limited applicability to small wind turbines because of its relatively high cost on the price of small wind turbine. Instead, stall control is generally applied in the blade design without any additional cost. However, stall delay can frequently be caused by high turbulence around the turbine blade, and it can produce control failures through excessive rotational speed and overpowering the electrical generator. Therefore, a passive pitch control module should be considered, where the pitch moves with the aerodynamic forces of the blade and returns by the elastic restoring force. In this study, a method to calculate the pitch moment, torque, and thrust based on the lift and drag of the rotating blade wing was demonstrated, and several effective wing shapes were reviewed based on these forces. Their characteristics will be estimated with variable wind speed and be utilized as basic data for the design of the passive pitch control module.