• Telecommunications review
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• v.24 no.4
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• pp.468-480
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• 2014

The current-generation avionics systems are based on a federated architecture, where an electronic device runs a single software module or application that collaborates with other devices through a network. This architecture makes the internal system architecture very complicate, and gives rise to issues of Size, Weight, and Power (SWaP). In this paper, we show that the partitioning defined by ARINC 653 can efficiently deal with the SWaP issues on small unmanned aerial vehicles, where the SWaP issues are extremely severe. We especially install the integrated mission system on real hexacopter and quadcopter and perform successful flight tests. The presented software technology for integrated mission system and software consolidation methodology can provide a valuable reference for other SWaP sensitive real-time systems.

• Review of KIISC
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• v.29 no.2
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• pp.29-35
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• 2019

CPS(Cyber Physical System)에 대한 사이버 공격이 다양해지고 고도화됨에 따라 시그니쳐에 기반한 악성행위 탐지는 한계가 있어 기계학습 기반의 정상행위 학습을 통한 비정상행위 탐지 기법이 많이 연구되고 있다. 그러나 CPS 보안 연구는 보안상의 이유로 CPS 데이터가 주로 외부에 공개되지 않으며 또한 실제 비정상행위를 가동 중인 CPS에 실험하는 것이 불가능하여 개발 기법의 검증이 어려운 문제가 있다. 이를 해결하기 위해 2015년 SUTD(Singapore University of Technology and Design)의 iTrust 연구소에서 SWaT(Secure Water Treatment) 테스트베드를 구성하고 36가지의 공격을 수행한 데이터셋을 공개하였다. 이후 국 내외에서 SWaT 테스트베드 데이터를 사용하여 다양한 보안 기법을 검증한 연구결과가 발표되고 있으며 CPS 보안에 기여하고 있다. 따라서 본 논문에서는 SWaT 테스트베드 데이터 및 SWaT 테스트베드 데이터에 기반한 비정상행위 탐지 연구를 분석한 내용을 설명하고, 이를 통해 CPS 비정상행위 탐지 설계의 주요 요소를 분석하여 제시하고자 한다.

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.32-37
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• 2016

Sidewall angle (SWA) of an absorber stack in extreme ultraviolet lithography mask is considered to be $90^{\circ}$ ideally, however, it is difficult to obtain $90^{\circ}$ SWA because absorber profile is changed by complicated etching process. As the imaging performance of the mask can be varied with this SWA of the absorber stack, more complicated optical proximity correction is required to compensate for the variation of imaging performance. In this study, phase shift mask (PSM) is suggested to reduce the variation of imaging performance due to SWA change by modifying mask material and structure. Variations of imaging performance and lithography process margin depending on SWA were evaluated through aerial image and developed resist simulations to confirm the advantages of PSM over the binary intensity mask (BIM). The results show that the variations of normalized image log slope and critical dimension bias depending on SWA are reduced with PSM compared to BIM. Process margin for exposure dose and focus was also improved with PSM.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.98-103
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• 1990

Brevibacterium lactofermentum SWA (arg trp) and B. lactofermentum SWB (met ser) were obtained from UV and NTG treatment. The rates of protoplast formation by B. lactofermentum SWA and SWB were 99.93% and 99.98%, respectively when each strain was treated with penicillin G in mid exponential growth phase, followed by incubation with 400 $\mu\textrm{g}$/ml of lysozyme in lysis fluid supplemented with 0.4M sucrose. Frequencies of protoplast regeneration in B. lactofermentum SWA and B. lactofermentum SWB were 9.27% and 10.32% respectively, on regeneration medium containing 0.5M sodium succinate, 50 mM $Mg^{2+}$, and 3% PVP. In intraspecific protoplast fusion between B. lactofermentum SWA and B. lactofermentum SWB, fusion frequency of $2.30\times 10^{-5}$ was observed by using the 100mM $CaCl_{2}$ and 30% PEG 6,000 in fusion fluid. Relative recombinant frequencies in each marker by means of selective media could be used for genetic analysis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.139-145
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• 2008

In this paper, a microstrip surface wave antenna(SWA) with a frequency selective surface structure(FSS) is designed and measured. A microstrip SWA has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated monopole like beam patterns. The microstrip SWA consists of two parts : a center-fed modified microstrip patch to excite surface wave, and a periodic patches to support the propagation of the surface waves. To obtain wide bandwidth, the ring type parasitic element is inserted and the circular patch is selected for the unit element in FSS structure. Experimental results show that the microstrip SWA has monopole like beam patterns at 5.9GHz. Impedance bandwidth and gain is 12% and 5.6dBi.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.23-28
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• 2011

This study was conducted to investigate the adsorption characteristics of various surfactants including biosurfactant, SWA 1503, Triton X-100 and sodium dodecyl sulfate(SDS) on soil. The Freundlich adsorption isotherm equation was found to be the best to describe experimental results. The amount of adsorbed surfactant on soil increased as the content of clay increased. The results showed that surfactant was adsorbed mainly on the surface and the pores of soil since the surface area of clay was larger than that of sand. The amount of adsorbed surfactants on soil was as follows: Biosurfactant > SWA 1503 > Triton X-100 > SDS.

• Journal of the Korean earth science society
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• v.29 no.4
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• pp.363-371
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• 2008

The purposes of this study were to analyze the level of Earth science vocabularies in the 10th grade textbooks with the Science Word Analysis (SWA) program and to investigate the vocabularies selected by the 10th grade students as difficult ones. For this purpose, we extracted the Earth science vocabularies from eleven textbooks, and classified into scientific and non-scientific vocabularies with the SWA program based on the standard Korean language dictionary. In addition, we investigated the difficulty of each vocabulary by surveying five hundred sixty students with a questionnaire. Results showed that the frequency of the scientific vocabularies that were beyond the designated level was the largest among any other levels in all textbooks. Most of the vocabularies selected by students as difficult ones to understand were classified into out of the level. From these results, it were suggested that the students' cognitive level should be considered when developing science textbooks and difficult vocabularies should be replaced with easy ones without a change of meaning.

• Journal of information and communication convergence engineering
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• v.14 no.1
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• pp.26-34
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• 2016

The alignment of DNA sequences is one of the important processes in the field of bioinformatics. The Smith-Waterman algorithm (SWA) performs optimally for aligning sequences but is computationally expensive. Field programmable gate array (FPGA) performs the best on parameters such as cost, speed-up, and ease of re-configurability to implement SWA. The performance of FPGA-based SWA is dependent on efficient cell-basic implementation-unit design. In this paper, we present an optimized systolic cell design while avoiding oversimplification, very large-scale integration (VLSI)-level design, and direct mapping of iterative equations such as previous cell designs. The proposed design makes efficient use of hardware resources and provides portability as the proposed design is not based on gate-level details. Our cell design implementing a linear gap penalty resulted in a performance improvement of 32× over a GPP platform and surpassed the hardware utilization of another implementation by a factor of 4.23.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.286-291
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• 1998

SAR has provided weather independent images on land and sea surface, which can be used for extracting various useful informations. Recently attempts to estimate wind field parameters from SAR images over the oceans have been made by various groups over the world. Although scatterometer loaded in ERS-1 and ERS-2 observes the global wind vector field at spatial resolution of 50 Km with accuracies of $\pm$2m/s in speed, the spatial resolution may not be good enough for applications in coastal regions. It is weil known the sea surface roughness is closely correlated to the wind field, but the wind retrieval algorithms from SAR images are yet in developing stage. Since the radar backscattering properties of the SAR images are principally the same as that of scatterometer, some previous studies conducted by other groups report the success in mesoscale coastal wind field retrievals using ERS SAR images. We have tested SWA (SAR Wind Algorithm) and CMOD4 model for estimation of wind speed using an ERS-1 SAR image acquired near Cheju Island, Korea, in October 11, 1994. The precise estimation of sigma nought and the direction of wind are required for applying the CMOD4 model to estimate wind speed. The wind speed in the test sub-image is estimated to be about 10.5m/s, which relatively well agrees to the observed wind speed about 9.0m/s at Seoguipo station. The wind speed estimation through the SWA is slightly higher than that of CMOD4 model. The sea surface condition may be favorable to SWA on the specific date. Since the CMOD4 model requires either wind direction or wind speed to retrieve the wind field, we should estimate the wind speed first using other algorithm including SWA. So far, it is not conclusive if the SWA can be used to provide input wind speed data for CMOD4 model or not. Since it is only initial stage of implementing the wind field retrieval algorithms and no in-situ observed data is currently avaliable, we are not able to evaluate the accuracy of the results at the moment. Therefore verification studies should be followed in the future to extract reliable wind field information in the coastal region using ERS SAR images.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.565-578
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• 2000

The aim of this study was development of the Straight-Wire Appliance(SWA) suitable lot the treatment or Korean. To accomplish the object of this study, Korean adult with normal occlusion were selected with following criteria : 1) no functional abnormality in the craniofacial area, 2) good dental arch form and posterior occlusal relationship, 3) Angle Class I occlusal relationship, 4) no experience of orthodontic, nor prosthodontic treatment, especially, no dental treatment on labial and buccal surfaces of teeth, 5) good racial profile. Impression were taken for upper and lower dental arches or the selected normal occlusion samples and the orthodontic dental stone models were fabricated. 5 well-trained orthodontists had examined the acquired dental stone models to select study samples which satisfy the Six keys to optimal occlusion of Andrews. 155 pairs of dental stone models (92 pairs of Male, 63 of Female) were finally selected. 3 dimensional digitization were performed with the Coordinate Measuring Machine(CMM, MPC802, WEGU-Messtechnik, Germany) and measuring of Angulation, Inclination, In-and-Out, Molar offset angle and Arch form were accomplished with a measuring software to achieve data for the development of SWA. Before the measurement, error study was performed on the 3 dimensional digitization with CMM, and the analysis of reliability of computerized measuring method adapted in this study and conventional manual method Presented by Andrews was performed. Results of this study were as to)lows : 1. Equi-distance digitization with mesh size 0.25 mm, 0.5 mm and 1.0 mm were acceptable in 3 dimensional digitization of dental stone model with the CMM, and the digitization with 1.0 mm mesh size was recommendable in terms of efficiency. 2. Computerized measuring method with 3 dimensional digitization was more reliable than manual measuring method of Andrews. 3. Data were collected for the development of SWA suitable for the morphological characteristics of Korean with the computerized measuring method with 3 dimensional digitization.