• Journal of Computing Science and Engineering
• /
• 제9권4호
• /
• pp.190-203
• /
• 2015

Free and open source software (FOSS) has created a large pool of source codes that can be easily copied to create new applications. However, a copy should preserve copyright notice and license of the original file unless the license explicitly permits such a change. Through software evolution, it is challenging to keep original licenses or choose proper licenses. As a result, there are many potential license violations. Despite the fact that violations can have high impact on protecting copyright, identification of violations is highly complex. It relies on manual inspections by experts. However, such inspection cannot be scaled up with open source software released daily worldwide. To make this process scalable, we propose the following two methods: use machine-based algorithms to narrow down the potential violations; and guide non-experts to manually inspect violations. Using the first method, we found 219 projects (76.6%) with potential violations. Using the second method, we show that the accuracy of crowds is comparable to that of experts. Our techniques might help developers identify potential violations, understand the causes, and resolve these violations.

• 정보과학회 컴퓨팅의 실제 논문지
• /
• 제23권2호
• /
• pp.134-139
• /
• 2017

기존의 스크린 미러링 시스템들은 패킷 손실에 취약하며 제한적인 모바일 기기의 에너지를 효율적으로 사용하지 못하는 단점을 가지고 있다. 이를 극복하기 위해 본 연구에서는 패킷 손실에 강인하고 에너지 효율적인 스크린 미러링 시스템을 제안한다. 제안하는 시스템은 패킷 손실로 인한 스크린 미러링 영상의 품질 저하를 완화하기 위해 전방오류정정 기술의 한 종류인 랩터 코드를 적용한다. 그리고 모바일 기기의 효율적인 에너지 사용을 위해 스크린 미러링 데이터에 대한 트래픽 셰이핑을 적용하고, 랩터 인코딩 매개 변수를 조절한다. 제안하는 시스템은 싱글 보드 컴퓨터를 사용하여 실제로 구현 되었으며, WiFi Direct 네트워크 상에서 성능을 검증하였다.

• 대한수학회지
• /
• 제53권4호
• /
• pp.795-834
• /
• 2016

The main purpose of this paper is to propose a scheme of a proof of the nonsimpleness of the group $Homeo^{\Omega}$ ($D^2$, ${\partial}D^2$) of area preserving homeomorphisms of the 2-disc $D^2$. We first establish the existence of Alexander isotopy in the category of Hamiltonian homeomorphisms. This reduces the question of extendability of the well-known Calabi homomorphism Cal : $Diff^{\Omega}$ ($D^1$, ${\partial}D^2$)${\rightarrow}{\mathbb{R}}$ to a homomorphism ${\bar{Cal}}$ : Hameo($D^2$, ${\partial}D^2$)${\rightarrow}{\mathbb{R}}$ to that of the vanishing of the basic phase function $f_{\underline{F}}$, a Floer theoretic graph selector constructed in [9], that is associated to the graph of the topological Hamiltonian loop and its normalized Hamiltonian ${\underline{F}}$ on $S^2$ that is obtained via the natural embedding $D^2{\hookrightarrow}S^2$. Here Hameo($D^2$, ${\partial}D^2$) is the group of Hamiltonian homeomorphisms introduced by $M{\ddot{u}}ller$ and the author [18]. We then provide an evidence of this vanishing conjecture by proving the conjecture for the special class of weakly graphical topological Hamiltonian loops on $D^2$ via a study of the associated Hamiton-Jacobi equation.

• 한국도서관정보학회지
• /
• 제30권1호
• /
• pp.1-29
• /
• 1999

이 연구의 목적은 대학도서관 자동화시스템의 품질을 평가하는 과정을 통해 도서관자동화의 현단계를 진단하고 현행 자동화시스템에서 발견되는 문제점을 치유하여 향후 보다 바람직한 시스템 구축을 위한 전략과 방안을 제시하는데 있다. 이를 위해, 서울대의 SOLARS, 포항공대의 LINNET, 그리고, 부산대의 PULIP (Vintage Las의 customized 형태)을 사례로 선정하여, 각 시스템의 개발과정에서 나타나는 특성과 문제점을 파악하였으며, 또한, 품질평가를 위한 객관적인 기준을 마련하여 각 시스템의 기능을 비교하였고, 나아가, 각 시스템의 장단점을 사서와 최종이용자의 관점에서 분석하였다. 이 연구를 통해 밝혀진 대학도서관 자동화시스템의 품질을 열악하게 만든 주요 요인은 : 계획 부재와 졸속 시행, 자동화 전문 인력의 부족, 시스템 중심의 개발 전략, 이용자의 행태에 대한 분석 결여, 도서관들 사이의 협조체계 미비, 과정에 대한 문서화 작업의 소홀, 그리고, 시스템에 대한 평가과정의 결여 등으로 요약된다.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
• /
• pp.251-255
• /
• 1999

Local field distribution in the mixed state of type II superconductors has been numerically calculated and compared with $^{11}$B NMR spectra for YNi$_2B_2C$ single crystals. We find that only small distortion of vortex positions from the perfect lattice points is enough to smear out the low frequency shoulder. As the vortices are further distorted, the line shape changes from an asymmetric shape with a high frequency tail to a symmetric Gaussian line shape. It is found that the second moment of the field distribution has a major contribution from the high frequency tail. Consequently, a linewidth of the full width at half maximum calculated from the second moment assuming for a Gaussian line shape is overestimated.

• 대한안전경영과학회지
• /
• 제10권3호
• /
• pp.117-126
• /
• 2008

RFID system the key technology of ubiquitous era, has been emphasized in logistics. Logistic enterprises are required to apply RFID systems considering their investment costs, actual effectiveness, operational satisfaction and so on. For such a purpose, many applicable methods of RFID system have been developed A method that RFID tags are directly attached to products or pallets is utilized in most cases. However, this method requires expensive investment cost, frequent replacement of damaged tags for the small and medium (SM) third party logistics. In this paper, we analyze statistically the current status and requirements of SM third party logistics. Based on their requirements, we propose the realtime warehousing-delivery management by the method to attach a RFID tag to each warehouse rack, together with the economy analysis index in order to evaluate economical efficiency. Consequently, this method is expected to reduce Investment cost and to improve operational effectiveness and satisfaction.

• 소성∙가공
• /
• 제27권4호
• /
• pp.222-226
• /
• 2018

Severe plastic deformation (SPD) is a promising method for drastically enhancing the mechanical properties of the materials by grain refinement of metallic materials. However, inhomogeneous deformation during the SPD process results in the inhomogeneous microstructure of the SPD-processed material. We manufactured cylindrical copper specimens of 42 mm in diameter with ultrafine grains (UFG) using an equal channel angular pressing (ECAP) to figure out the relationship between homogeneous microstructure and the number of the processing passes. Two specimens, which are ECAP-processed 4 times (4pass) and 6 times (6pass) each with Route Bc, are prepared for comparison of mechanical properties and microstructure. The results show that the mechanical properties of the two specimens (4pass and 6pass) are similar. Moreover, both the specimens show highly enhanced mechanical properties. The 4pass specimen, however, shows inhomogeneity in hardness distribution, while the 6pass specimen shows a homogeneous distribution. Microstructure analysis reveals that the 4pass specimen has an inhomogeneous microstructure with incompletely refined grain structure. This inhomogeneity of the 4pass specimen could be explained by the circumferential rotation during ECAP process.

• 한국전자파학회논문지
• /
• 제14권9호
• /
• pp.979-984
• /
• 2003

인체에 사용되는 삽입형 안테나가 새롭게 제안되었다. 이 안테나의 동작 주파수는 2.45 GHz이며, coaxial cable과 리엑턴스 성분으로 구성되어 있다. 이 리엑턴스 성분은 안테나 끝에 존재하며 거의 완전한 정합과 가열되는 영역을 넓히는데 기여한다. 완전한 안테나 정합을 위하여 전송선로 이론에 기초한 정합방법을 제시하였고 그 정합 방법을 이용하여 이 안테나가 근육에 삽입되었을 때 완전한 정합이 이루어지도록 안테나를 제작, 실험하였다. 측정된 반사계수는 -28.377 dB로써, 지금까지 문헌에 보고된 가장 좋은 결과이다. 그렇기 때문에, 하나의 안테나로도 간, 뇌, 심장과 같이 인체 깊숙이 존재하는 종양이나, 암 세포를 제거하는데 사용될 수 있음을 보여주고 있다.

• Journal of Electrical Engineering and Technology
• /
• 제1권1호
• /
• pp.110-113
• /
• 2006

A high rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The power supply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The pulse repetition rate and the duty were changed in the ranges of $10\sim50$ kHz and $10\sim60%$, respectively. The deposition rate increased with rising incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW. This result shows higher deposition rate than any other previous work involving reactive sputtering in oxide mode. The thickness uniformities over the entire substrate area of $982mm{\times}563mm$ were observed at the processing pressure of $2.8\sim9.5$ mTorr. The thickness distribution was improved at lower pressure. This technique is proposed for application to a high through-put sputtering system for plasma display panels.

• 제어로봇시스템학회논문지
• /
• 제21권9호
• /
• pp.807-810
• /
• 2015

In this paper, a finite impulse response(FIR) fixed-lag smoother is proposed for discrete-time nonlinear systems. If the actual state trajectory is sufficiently close to the nominal state trajectory, the nonlinear system model can be divided into two parts: The error-state model and the nominal model. The error state can be estimated by adapting the optimal time-varying FIR smoother to the error-state model, and the nominal state can be obtained directly from the nominal trajectory model. Moreover, in order to obtain more robust estimates, the linearization errors are considered as a linear function of the estimation errors. Since the proposed estimator has an FIR structure, the proposed smoother can be expected to have better estimation performance than the IIR-structured estimators in terms of robustness and fast convergence. Additionally the proposed method can give a more general solution than the optimal FIR filtering approach, since the optimal FIR smoother is reduced to the optimal FIR filter by setting the fixed-lag size as zero. To illustrate the performance of the proposed method, simulation results are presented by comparing the method with an optimal FIR filtering approach and linearized Kalman filter.