RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      • 좁혀본 항목

      • 좁혀본 항목 보기순서

        • 원문유무
        • 음성지원유무
        • 원문제공처
        • 등재정보
        • 학술지명
        • 주제분류
        • 발행연도
        • 작성언어
        • 저자

      오늘 본 자료

      • 오늘 본 자료가 없습니다.
      더보기
      • 무료
      • 기관 내 무료
      • 유료
      • KCI등재
      • SCIESCOPUSKCI등재

        New Control Method for Power Decoupling of Electrolytic Capacitor-less Photovoltaic Micro-Inverter with Primary Side Regulation

        Irfan,,Mohammad,Sameer,Shin,,Jong-Hyun,Park,,Joung-Hu The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

        This paper presents a novel power decoupling control scheme with the bidirectional buck-boost converter for primary-side regulation photovoltaic (PV) micro-inverter. With the proposed power decoupling control scheme, small-capacitance film capacitors are used to overcome the life-span and reliability limitations of the large-capacitance electrolytic capacitors. Then, an improved flyback PV inverter is employed in continuous conduction mode with primary-side regulation for the PV power conditioning. The proposed power-decoupling controller shares the reference for primary side current regulation of the flyback PV inverter. The decoupling controller shapes the input current of the bidirectional buck-boost converter. The shared reference eliminates the phase-delay between the input current to the bidirectional buck-boost converter and the double frequency current at the PV primary current. The elimination of the phase-delay in dynamic response enhances the ripple rejection capability of the power decoupling buck-boost converter even with small film capacitor. With proposed power decoupling control scheme, the additional advantage of the primary-side regulation of flyback PV inverter is that there is no need to have an extra current sensor for obtaining the ripplecurrent reference of the decoupling current-controller of the power-decoupling buck-boost converter. Therefore, the proposed power decoupling control scheme is cost-effective as well as the size benefit. A new transient analysis is carried out which includes the source voltage dynamics instead of considering the source voltage as a pure voltage source. For verification of the proposed control scheme, simulation and experimental results are presented.

      • KCI등재SCOPUS

        Evaluation of Risk Factors Causing Cost Overrun in Road Projects in Terrorism Affected Areas Pakistan – a Case Study

        Irfan,Zafar,Tashfeen,Yousaf,Sarfraz,Ahmed 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

        The risks and uncertainties inherent to the construction industry are more than any other industry and this industry exhibits poor management of these risks. Hence, many projects fail to meet time schedules and budget targets. Transport sector is an important part of the construction industry and is vital to its growth. However this sector has been severely affected by delayed completion of the projects with exceeded cost. These issues are more pronounced in terrorism affected areas around the world, predominantly in Pakistan, Afghanistan and Iraq. Evaluation of Risk Factors Causing Cost Overrun in Road Projects in Terrorism Affected Areas: Pakistan - a Case Study. Pakistan being top ranked terrorism affected country among 85 terrorist affected countries around the world in 2012, has been taken as case study. In Pakistan, Federally Administrated Tribal Area (FATA) being the recipient of max casualties in 2012 is the focus of the study. After 9/11, FATA received maximum share of development projects especially road infrastructure however, these projects could not fulfill their desired purpose due to lack of evaluation of risks associated with the dynamics and culture of that area resulting in severe cost overrun of these projects. This study presents the mechanism to identify the key risk factors contributing to the failure of achieving budget targets of road projects in FATA and suggests measures to overcome them. The study is undertaken via a questionnaire based survey comprising of 18 cost overrun risk factors which were ranked using their mean weightage. Analysis of the results show that non-availability of suitable contractors, project location within FATA, idling cost of plant and equipment due to security threats, differing site conditions in a project and inaccurate survey and site investigation due to security threat were major factors responsible for cost overrun. Moreover, responsibility among the stakeholders for these risks was also established. The results of the study warrant adoption of proactive measures for effective management of these risks by owner, consultants and contractors to avoid budget escalation in road construction projects in terrorism affected area around the world.

      • An Application of Educational Data Mining (EDM) Technique for Scholarship Prediction

        Irfan,Ajmal,Khan,Jin,Tak,Choi 보안공학연구지원센터 2014 International Journal of Software Engineering and Vol.8 No.12

        Mining data in educational filed is an important and useful task for anybody related to educational institute. The useful information mined from the data can help with performance, guidance, teaching, planning and etc. for staff, students and instructors. Different educational data mining researches has been carried out on student data which includes the student's basic achievements and educational background, academic scores and the amount of credit hours, but the relations between these are limited. Therefore in this paper we have described a system using data mining technologies such as decision tree. We have analyzed ID3 and J48 (C4.5) algorithms for predicting the scholarship winning chances on student data by translating the decision tree into “IF-THEN” rules and implementing these rules for prediction in our system called scholarship calculator. We have mined student data to calculate the chances of winning scholarship depending on their semester grades, position/rank of student in class, achievements, maximum and minimum amount of taken and allowed credit hours and extra curriculum activities. We found that ID3 works better even though J48 is faster in classifying data and creates a smaller tree than ID3. Because of ID3's bigger tree it has more rule, more rules means more crosschecking and deeper decision, that's why the predicted result was more accurate than J48. We have also described how our scholarship calculator works to predict and calculate the chances of winning scholarship. Performance evaluation is done and the results are also compared with already existing datasets. The developed system could be very useful in predicting student's chances of winning scholarship from the first semester. It can help students to pinpoint the weak areas, which can be perfected with proper guidance from instructors and staff for better chances of winning scholarship.

      • KCI등재SCOPUS

        Evaluating the Performance of Remotely Sensed Precipitation Estimates against In-Situ Observations during the September 2014 Mega-Flood in the Kashmir Valley

        Irfan,Rashid,Ajaz,Ahmad,Parray,Shakil,Ahmad,Romshoo 한국기상학회 2019 Asia-Pacific Journal of Atmospheric Sciences Vol.55 No.2

        In the present study, 4 gridded satellite precipitation data products for September 2014 flood, IMERG (Integrated Multi-satellitE Retrievals for GPM), GSMaP (Global Satellite Mapping of Precipitation), TRMM-3B42 (Tropical Rainfall Measuring Mission) and INSAT-3D-IMR (INSAT Multispectral Rain), were evaluated against the Indian Meteorological Department rain-gauge data from Sep-1st to Sep-7th 2014. Three evaluation indices; Correlation coefficient (CC), the Relative bias (RB) and the Nash- Sutcliffe coefficient (NSC), were used to evaluate the robustness of satellite precipitation estimates with actual rainfall measurements. IMERG precipitation product has a near perfect positive CC and NSC values of 0.94 and 0.99 respectively; while the CC and NSC values are 0.7 and 0.5 for GSMaP_Gauge; 0.69 and 0.05 for INSAT-3D-IMR; and 0.9 and 0.8 for TRMM-3B42 respectively. The RB estimates indicate that IMERG, with a bias of 2%, is a best-fit dataset when compared to the surface raingauge observations. In contrast, TRMM-3B42, GSMaP and INSAT-3D-IMR have underestimation biases of −31%, −58%, and − 86%respectively. Analysis of the indices indicates that IMERG precipitation product performed better than other three satellite precipitation products owing to the closeness of values with surface gauge station data over Kashmir. Owing to scanty observation of rainfall in the region, IMERG has a potential to become a cost effective input data source for designing a flood early warning system (FEWS) for Kashmir. However, it is suggested to evaluate the robustness of different satellite-derived precipitation estimates compared to rain gauge observations by incorporating more extreme events from different mountain regions globally for establishing the best satellite derived precipitation product.

      • KCI등재

        Cloning, expression, molecular modelling and docking analysis of steroidogenic acute regulatory protein (StAR) in Clarias batrachus

        Irfan,Ahmad,Bhat,Rupam,Sharma,Mohd,Ashraf,Rather,Pravesh,Kumar,Rathor,P.,Gireesh‑Babu,Mukunda,Goswami,J.,K.,Sundaray 한국유전학회 2017 Genes & Genomics Vol.39 No.9

        The steroidogenic acute regulatory protein (StAR) plays a key role in transferring cholesterol across the inner mitochondrial membrane. In this study, the StAR gene was isolated from the gonads of Clarias batrachus. The gene has an open reading frame of 857 bp and encodes 285 amino acids with a predicted molecular weight of 32 kDa. The signalP analysis predicted that StAR would be a non-secreted protein that lacks a signal peptide. The subcellular localization demonstrated that the presence of the StAR protein was higher in mitochondria (41.8%), followed by the nuclear region (37.1%) and cytoplasm (11.1%). The StAR protein was found to interact highly with cyp11a1, followed by the cytochrome P450 family 11 proteins and the START5 domain. The homology modelling revealed that the protein has 4 helices and twisted U-shaped 10 beta sheets numbered from αA to αD and β1 to β10, respectively. Molecular modelling analysis showed that resveratrol and eurycomanone has high binding affinity with the StAR protein. The C. batrachus StAR transcript was found to be expressed exclusively in the gonads, kidney, and liver. These results overall lay a solid foundation for understanding the structure of StAR protein in fish. The identification of 3D structures and binding sites will help in designing a structure-based drug of StAR agonists for the treatment of impaired steroidogenesis.

      • H-23 : NO oxidation over Pt based catalysts for Hybrid fast SCR process

        ( Irfan Muhammad Faisal ), 구정회 김상돈) 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.2

        Different catalysts containing platinum were studied for the oxidation of NO with various concentrations of oxygen, nitrogen monoxide and nitrogen dioxide. The order of activity for oxidation reaction was found to be: Pt/WO3/TiO2 anatase > Pt/TiO2 rutile > Pt/Al2O3. Moreover anatase and rutile has same chemistry i.e. TiO2 but different structure. The conversion of NO to NO2 increases with increasing oxygen concentration from 3 to 10%, but it levels off at higher concentrations. The conversion to NO2 decreases with increasing feed concentrations of NO and also decreases by the addition of NO2 to the feed. Both these observations suggest that the oxidation of NO on Pt based catalysts is autoinhibited by the reaction product NO2. Further experiments were performed for the oxidation of SO2 and its effects on NO oxidation. NO conversion was slightly decreased by the effect of SO2 over anatase catalysts but highly affected by SO2 over rutile catalyst. On the other hand, the presence of NO showed remarkbly high conversion of SO2 over all catalysts.

      • KCI등재

        A proposed image stitching method for web-based panoramic virtual reality for Hoseo Cyber Museum

        Irfan Khan(아르판 칸), Hong Song Soo(홍성수) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.2

        파노라마 가상현실이란 특정 장소의 경험을 재현하는 방식으로, 현실 세계의 장소에 직접 가보지 않고 가상 현실 속의 사물이나 정보를 보다 쉽고 빠르게 탐색하고 습득 할 수 있다. 본 논문에서는, 우리는 이상적인 키 포인트 를 탐지하는 동적 프로그래밍을 사용하여 함께 이 지점과 인접한 이미지를 병합하고, 부드러운 색상 전환을 위해 이 미지를 혼합하는데 사용된다. FAST와 SURF 탐지는 이미지의 확실한 특징을 찾는데 사용되고, 가장 가까운 이웃 알 고리즘은 해당되는 특징을 일치시키는데 사용되며, RANSAC을 사용하여 일치하는 키 포인트를 homography로 판단한 다. 이러한 방법으로 이미지를 자동 선택하여 스티칭하는 방법을 사용한다. It is always a dream to recreate the experience of a particular place, the Panorama Virtual Reality has been interpreted as a kind of technology to create virtual environments and the ability to maneuver angle for and select the path of view in a dynamic scene. In this paper we examined an efficient method for Image registration and stitching of captured imaged. Two approaches are studied in this paper. First, dynamic programming is used to spot the ideal key points, match these points to merge adjacent images together, later image blending is used for smooth color transitions. In second approach, FAST and SURF detection are used to find distinct features in the images and nearest neighbor algorithm is used to match corresponding features, estimate homography with matched key points using RANSAC. The paper also covers the automatically choosing (recognizing, comparing) images to stitching method.

      맨 위로 스크롤 이동