A Venture Capital Portfolio Model Based on Considering the allocation of both Capital Investment and management input

Peng Fei,Zhang Wei-guo,Tang Hai-rong 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

The essence of Venture Capital is to nurture entrepreneurship and development by Capital support and consultive management services, which shows that venture capitalists" management support is of the same importance to the success of venture businesses as the capital support. The inputs of management and the investment of capital will together affect venture capitalists" specific choices of venture businesses. Assume that venture capitalists and venture entrepreneurs can reach an optimal contract, we put forward management input influence coefficient function, discussed its characters and constructed a general venture capital portfolio model and simplified model based on variance analysis by defining an management input impact factor and an expected profit function of a venture capital portfolio which is affected by the management input. A numerical example showed that optimize the allocation of funds and management input synthetically is very important for venture capital porfolio.

An Eyelid Detection Algorithm for the Iris Recognition

Pengfei Cai,Chongke Wang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.5

To reduce the influence of the eyelid for the iris recognition rate, an eyelid detection algorithm for the iris recognition is proposed. The grayscale morphological operations are employed to remove the interference of the eyelash and the light spot to the eyelid region. The points of the minimum grayscale value of each column in the eyelid region are extracted as edge points. The least squares parabolic fitting eyelids is carried out for the edge points of the eyelid. The eyelid parabolic moving up and down in neighborhood region is used to localizing the eyelid precisely, when the grayscale mutation happens. The experimental results show that the eyelid localization algorithm can detect the eyelid effectively and quickly. Compared with the hough transform algorithm, the accurate rate is the same, but the speed is improved about 4 seconds.

Numerical studies on cavitation behavior in impeller of centrifugal pump with different blade profiles

Pengfei Song,Yongxue Zhang,Cong Xu,Xin Zhou,Jinya Zhang 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.2

To investigate the influence of blade profiles on cavitation behavior in impeller of centrifugal pump, a centrifugal pump with five different blade profiles impellers are studied numerically. The impellers with five different blade profiles (single arc, double arcs, triple arcs, logarithmic spiral and linear -variable angle spiral) were designed by the in-house hydraulic design code using geometric parameters of IS 150-125-125 centrifugal pump. The experiments of the centrifugal pump have been conducted to verify numerical simulation model. The numerical results show that the blade profile lines has a weak effect on cavitation inception near blade inlet edge position, however it has the key effect on the development of sheet cavitation in impeller, and also influences the distribution of sheet cavitation in impeller channels. A slight changing of blade setting angle will induce significant difference of cavitation in impeller. The sharp changing of impeller blade setting angle causes obvious cavitation region separation near the impeller inlet close to blade suction surface and much more flow loss. The centrifugal pump with blade profile of setting angle gently changing (logarithmic spiral) has the super cavitation performance, which means smaller critical cavitation number and lower vapor cavity volume fraction at the same conditions.

Autonomous Driving Using Artificial Potential Function for Vehicle Collision Avoidance

Pengfei Lin,Woo Young Choi,Jin Ho Yang,Chung Choo Chung 제어로봇시스템학회 2020 제어로봇시스템학회 국내학술대회 논문집 Vol.2020 No.7

Finite groups all of whose maximal subgroups are SB-groups

Pengfei Guo,Junxin Wang,Hailiang Zhang 대한수학회 2014 대한수학회보 Vol.51 No.4

A finite group G is called a SB-group if every subgroup of G is either s-quasinormal or abnormal in G. In this paper, we give a complete classification of those groups which are not SB-groups but all of whose proper subgroups are SB-groups.

Comparison between laparoscopic and abdominal radical hysterectomy for stage IB1 and tumor size <2 cm cervical cancer with visible or invisible tumors: a multicentre retrospective study

Pengfei Li,Lan Chen,Yan Ni,Jiaqi Liu,Donglin Li,Jianxin Guo,Zhihua Liu,Shuangling Jin,Yan Xu,Zhiqiang Li,Lu Wang,Xiaonong Bin,Jinghe Lang,Ping Liu,Chunlin Chen 대한부인종양학회 2021 Journal of Gynecologic Oncology Vol.32 No.2

Objective: To compare 5-year disease-free survival (DFS) and overall survival (OS) rates oflaparoscopic radical hysterectomy (LRH) and abdominal radical hysterectomy (ARH) forstage IB1 and tumor size <2 cm with visible or invisible tumors. Methods: We retrospectively compared the oncological outcomes of 1,484 cervical cancerpatients with IB1 and tumor size <2 cm on final pathology, who received ARH (n=899) or LRH(n=585) between January 2004 and December 2016. Patients were divided into visible tumorsubgroup (ARH: n=668, LRH: n=444) and invisible tumor subgroup (ARH: n=231, LRH:n=141) according to tumor type. Results: LRH and ARH showed similar 5-year DFS and OS rates (93.3% vs. 93.1%, p=0.997;96.2% vs. 97.5%, p=0.351) in total study population. LRH was not associated with worse5-year DFS rate (hazard ratio [HR]=0.96; 95% confidence interval [CI]=0.58–1.58; p=0.871)or OS rate (HR=1.37; 95% CI=0.65–2.89; p=0.409) by multivariable analysis. In the visibletumor subgroups, LRH and ARH showed similar 5-year DFS and OS rates (91.9% vs. 91.9%,p=0.933; 95.0% vs. 96.9%, p=0.276), and LRH was not associated with worse 5-year DFS orOS rate (p=0.804, p=0.324). In the invisible tumor subgroups, LRH and ARH also showedsimilar 5-year DFS and OS rates (97.3% vs. 97.1%, p=0.815; 100% vs. 99.5%, p=0.449), andLRH was not associated with worse 5-year DFS rate (p=0.723). Conclusions: Among patients with stage IB1 and tumor size <2 cm, whether the tumor isvisible or not, the oncological outcomes of LRH and ARH among cervical cancer patients arecomparable. This suggests that LRH may be suitable for stage IB1 and tumor size <2 cm withvisible or invisible tumors.Trial Registration: International Clinical Trials Registry Platform Identifier: CHiCTR180017778

Distortion Minimization in Wireless Sensor Networks With Energy Harvesting

Pengfei Du,Qinghai Yang,Zhong Shen,Kyung Sup Kwak IEEE 2017 IEEE communications letters Vol.21 No.6

<P>In this letter, we investigate the distortion minimization problem by jointly optimizing the sleep-wake scheduling and the transmit power in energy harvesting wireless sensor networks. A mean square error minimization problem with a more efficient harvest-use-store architecture and limited available channels taken into account is formulated. To tackle this mixed-integer non-linear programming, we first transform it into a tractable convex problem through the integer relaxation. Subsequently, a low-complexity sleep-wake scheduling and power control algorithm is proposed to solve the transformed problem. Specifically, we uncover the special structure of the transformed problem and employ it to obtain the optimal sleep-wake policy and power allocation for each sensor node.</P>

A Light-weight Mitigation Scheme on the Mole Content Poisoning Attack in NDN

Pengfei Yue,Ru Li,Bin Pang 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09

With a novel content-based communication model that is designed for data sharing, Named Data Networking (NDN) borns with innate security by per package encryption and achieves better scalability and mobility. Security attacks in the current Internet, e.g., IP and/or DNS spoofing, can hardly hazard NDN since there is no address and the embedded security in the data packet. However, some new kinds of attacks (e.g., interest flooding attack and content poisoning attack) damage NDN if not investigated thoroughly. In NDN, there exists a variant of content poisoning attack (CPA) that the attack is launched by some compromised core routers and this kind of attack causes severe damage to the network. In this paper, this variant of CPA has named the mole content poisoning attack (MCPA), and a Kalman filter based light-weight mitigation scheme is proposed. Besides, random sampling is imposed on the data traffic and tunes the state parameters in the Kalman filter to achieve faster convergence in a router. Compared with the mitigation scheme by the probabilistically checking of signatures on the data traffic, the proposed light-weight mitigation scheme recovers interest satisfaction rates (ISRs) of consumers while introducing less computation overhead.

A Study on Gamification as a Key Role in Future Civilization : Focused on the Feature of Virtual Reality

( Pengfei Li ),( Woon-hyung Lee ) 한국디자인트렌드학회 2019 한국디자인포럼 Vol.24 No.3

Background: : It is believed that human beings have gone from 100,000 years ago to the present. They have experienced the degeneration of primitive civilization to scientific and technological civilization, completed the first leap of human civilization, and brought humanity into a highly intelligent social division of labor. Human beings have also become their own weaving. A node in the network of meaning. The game is the ninth art of mankind and the inevitable outcome of the interactive era. Some people think that it is a flood of beasts, it is an "addictive" entertainment "drugs." However, some people think that it is the future of mankind, and it is the means for human civilization to leap from the real world to the virtual world. We look at the future of mankind from the perspective of history and the development of science and technology. We find that the future brought to us by our games is looming. Methods: This paper aims to explore the relationship between gamification and civilization, also foresight the possibility of the next step of human civilization. In order to achieve this aim, previous researches, books and websites are examined and author’s work experience of relevant industries in many years are used as well. Results: Under the social division of high-tech civilization, we actively seek for the most authentic needs of mankind. Clear goals, limited rules, real-time feedback mechanisms, and proactive participation are common thinking we get from games. In the powerful torrent of technological development, we use artificial intelligence, big data, and virtual reality technology to practice in human society. Used in educational work and entertainment life. Conclusion: Virtualization is the carrier of human beings carrying civilization. Causality is the means by which humans perceive the world. Gaming is the tool for human beings to move into the future. Although we can't predict the specific appearance of the future, we can look into the future with historical perspective and strong and strong curiosity about scientific and technological progress.

Design and motion analysis of load-carrying and transmit robot (LCT-Robot) for small openings

Pengfei Wang,Qixin Cao 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

This paper proposes a Load-carrying and transmit robot (LCT-Robot), which is based on a novel modular joint, for the purpose of telemaintenance of the Tokamak First wall (FW). The LCT-Robot, which is installed on a Multipurpose transport cask (MTC) and plays the role of transmitting and load-carrying, has the adaptability to several of maintenance tasks by carrying different types of micro-robots. The transmission mechanism of LCT-Robot modular joint and structural "lightweight" design is comprehensively considered through establishing the geometric parameter constraint equations related to Tokamak FW. It can steadily provide the ability of long-distance transmitting and performs maintenance tasks when the weight of the micro-robot is changed. Without any gravity compensation, the LCT-Robot equipped with ordinary drive motor can bear a wide range of load. It not only satisfies the higher load, but also enhances the efficiency of the drive motor. For avoiding frequent acceleration and deceleration of the LCT-Robot, the entire process through small openings from the placement state (0-state) to the flattened state (3-state) is analyzed and the effective translational distance of MTC is confirmed. As a result, experiment verifies the effectiveness of the LCT-Robot, which has a length of 2.95 meters and can smoothly pass through small openings (Width: 200 mm, Height: 250 mm).