Expanding constraint theory to determine well-posedness of large mathematical models

Phan, Phan University of Southern California 2011 해외박사(DDOD)

Mathematical modeling represents one of the major tools for the conception and management of the ever increasing complexity of systems engineering. Unfortunately, present approaches to math modeling suffer from several theoretical problems which include: model consistency, computational allowability, management of the topologically complex flow of software algorithms, rearrangement of independent and dependent variables, distinction between the model structure and software programs and perhaps the most challenging, the exponential explosions resulting from the management of even medium sized models as well as the large models of the thousands of dimensions necessary to define and manage the complex systems of the future. Constraint theory was designed to solve the above problems employing a rigorous application of graph theory and attempts to employ the generalizability of mathematics to extend the math model manager's conceptual understanding from half a dozen dimensions to the desired thousands of dimensions. Constraint theory (CT) went through several stages of detail and maturity, starting with the PhD dissertation in the 1960's and progressing through several papers and two other PhD research programs. CT's present frontier can be characterized by the Constraint Theory book written by Dr. George Friedman and published by Springer in 2005. CT differs from linear programming (LP) in several ways. LP requires a full model of explicit mathematical expressions in linear form whereas CT employs a meta-model based upon relevancy between general (linear or non-linear) relations and variables. CT seeks to determine a model consistency and computational allowability without having to actually solve for a specific solution set whereas LP assumes that the problem is well-posed while attempting to solve for an optimal solution within a given constrained trade space. As mentioned above, the exponential explosions associated with the management of thousand-dimensional models is truly enormous, on the order of 2 N examinations of a model's N equations are required to determine consistency, for example. CT has converged this process---which would take several universe lifetimes even with nanosecond computer cycle times---by a factor of trillions. This convergence is based on an ordered series of graph theoretic steps involving connected-ness, tree-ness, circuit-ness and cluster-ness. A constraint theoretic structure called the "Basic Nodal Square" (BNS) is identified as the kernel of constraint in a math model. An n x n BNS is essentially a complete sub-system of n relations and n variables within the overall model. However, Friedman's book effectively stops at the identification of circuit clusters of approximately 30 relations, and suggests that BNS within these clusters can be found by modern computers in a few hours. It is suggested that perhaps more research can employ the topological property of adjacency to converge the search for BNS within larger circuit clusters. The central contribution resultant from this investigation realizes and improves the computational efficiency of BNS search by factors of trillions, asymptotically (see Figure 10-2). This improvement has been accomplished by innovative application of graph theory, topology, algorithm analysis and linear algebra, which were not addressed to sufficient depth in the original efforts. Leveraging research results in graph theory since the early 1970's, several BNS search methods, based on nodal adjacency, circuit adjacency and nodal degree, have been developed and compared against the baseline (brute-force) approach of 2N. Primary key research findings and enablers include: (a) Decomposition of a model graph into its connected components by employing the graph-theoretic concept of a spanning tree and applying the depth-first search algorithm. (b) Innovation of the edge-centric method, over the legacy approach of vertex-centricity, to identify, and remove, internal trees (or bridges) within a connected component. (c) Further isolation of circuit clusters containing potential BNS by using the graph-theoretic concept of articulation point (or separating vertex). (d) Rigorous proof of circuit vector-based theorems to simplify the computational complexity of constructing unions of adjacent circuits, and thus reduce BNS search space. (e) Application of vectorial dot product to detect adjacency among circuits, and overlapping among nodes or BNSs. (f) Development and demonstration of a meta-meta-model graph to represent overlapping among nodes and to reduce the solution-time for BNS search, from exponential to polynomial. Additional accomplishments further improve the utility of CT by developing an integrated set of efficient computing algorithms to determine model consistency and computational allowability. The output of these algorithms can also advise the model builder of repair alternatives to correct any model inconsistency detected. Such algorithms are necessary to bridge the gap between theoretical abstracts and practical realization of CT in terms of an effective computer-assisted tool for math model management.

Chemical vapor deposition growth and high-k dielectric properties of hydrofluorocarbon films

PHAN THI KIM UYEN 忠南大學校 大學院 2024 국내석사

Chemical vapor deposition growth and high-k dielectric properties of hydrofluorocarbon films Phan Thi Kim Uyen Department of Materials Science and Engineering, Graduate School Chungnam National University Daejeon, Korea (Supervised by Professor Eui-Tae Kim) High-k dielectrics are crucial parts of the present generation and prospective electronic circuits. In complementary metal-oxide-semiconductor (CMOS) structures, particularly, they have been broadly studied for modern memory devices and logic microelectronics. In accordance with Moore's rule, an integrated circuit's transistor count doubles every two years, and the size of the transistors also shrinks predictably. To maintain transistor functionality, the gate dielectric thickness will be reduced to less than the oxide equivalent thickness (EOT) of a deca-nanometer, leaving high-k materials as the only practical option for such a small-scale EOT. However, for sub- 10nm thickness of about 1-2nm is beyond their elementary material limits forced by electron tunneling effect. Most of studies on high-k dielectric materials have been concentrated on inorganic thin film including metal oxides (MOs), nitrides (Si3N4, AlN), perovskites, and hybrids comprising them. Intriguingly, novel class of propitious candidates are organic such as fluorocarbon (FC), hydrocarbon (HC) or the most recent hydrofluorocarbon (HFC), irrespective of the fact how low-k they are commonly considered. An amorphous carbon monolayer, for example, is a strong insulator. HFC films (HFCs) have carbon backbones with hydrogen and fluorine atoms that distribute randomly along different sides of the backbone carbon atom. This affects the electric and dielectric properties of an HFC. As a result, HFCs with high k values show promise. A brief literature review on ultrathin high-k dielectric films of HFC films were fabricated and their exceptional features were utilized to develop the applications in metal-insulator-semiconductor (MIS) devices. For further application, they were employed as surface passivation layers in graphene field-effect transistors (GFET) to suppress Coulomb scattering from adsorbing ambient environment of graphene channel fabricated by inductively-coupled plasma chemical vapor deposition (ICP- CVD) using the plasma gas mixtures (CH4, CF4 and H2). This approach supplies a straightforward and commercial fabrication of high-k dielectric thin films for prospective applications in microelectronic devices. The surface passivation of HFC films for the enhanced mobility of graphene channel. This emergent structure is an auspicious candidate used as affordable, effective, and simple high-k dielectric films for alternatives of CMOS devices to provide insights for future research.

Research on insurance fraud and regulations on prevention of automobile insurance fraud : experiences from the United States of America and proposals for Vietnam

Phan, Thi Huong Giang TLBU Graduate School of Law 2019 국내석사

Defending denial-of-service attacks in SDNFV-enabled cloud computing

Phan, Van Trung Soongsil University 2017 국내석사

In my thesis, I propose a novel S2eH scheme to tackle Denial-of-Service (DoS) attacks in the Software-Defined Network Functions Virtualization (SDNFV) cloud computing environment. I firstly introduce a new machine learning hybrid model for DoS attack classification based on Support Vector Machine (SVM) and Self Organizing Map (SOM) algorithms to enhance the performance of classification network traffic. The proposed combination mainly focuses on taking advantages of two classification algorithms by utilizing both algorithm advantages that SVM takes a little time to produce outputs with a high accuracy and SOM makes a reliable prediction based on their neurons. Then, I propose an enhanced History-based IP Filtering scheme (eHIPF) to improve attack detection rate and speed. Finally, I propose a novel mechanism combining both the machine learning hybrid model SVMs-SOM and the eHIPF scheme, called S2eH, to make a DoS attack defender in the SDNFV-enabled cloud computing. The S2eH testbed is implemented in the SDNFV cloud environment with Service Function Chaining. Through practical experiments in this testbed, it is proved that the proposed SVMs-SOM combination and eHIPF scheme outperforms existing mechanisms for DoS attack classification and detection. By analyzing comprehensive experiments conducted with various DoS attack levels, I prove that the novel S2eH mechanism is an effective and innovative approach to defend DoS attacks in the SDNFV-based cloud computing. 본 논문에서는 Software-Defined Network Functions Virtualization (SDNFV) Cloud computing 환경에서 서비스 거부 공격을 저지하는 새로운 S2eH 스키마를 제안한다. 먼저, DoS 공격 분류를 위해 Network 분류 성능을 높이는 Support Vector Machine (SVM) 과 Self-Organizing Map(SOM) 알고리즘 기반 새로운 Hybrid Machine Learning을 소개한다. 제안된 결합 시스템은 주로 두 가지 분류 알고리즘의 이점을 가져오는데 초점을 둔다. SVM은 짧은 시간에 높은 정확도로 분류를 하고, SOM은 SOM의 신경망기반으로 신뢰성이 높은 예측을 한다. 또한, 공격 탐지 비율과 속도를 개선하기 위해 History 기반 IP Filtering 스키마(eHIPF)를 제안한다. 본 논문에서는 SDNFV가 가능한 Cloud Computing 에서 DoS공격을 방어하기 위해 SVMs-SOM을 결합한 Hybrid Machine Learning 모델과 eHIPF 스키마를 결합한 새로운 메커니즘 S2eH을 제안한다. S2eH testbed는 Service Function Chaining이 가능한 SDNFV Cloud 환경에서 실험했다. 이 testbed에서 실제 실험을 통해 본 논문에서 제안된 SVMs-SOM 결합과 eHIPF 스키마가 DoS공격 분류와 탐지에 다른 메커니즘보다 좋은 결과 가져오는 것을 증명했다. 다양한 DoS공격 레벨로 수행 된 포괄적인 실험을 분석하여 새로운 S2eH메커니즘이 SDNFV기반 Cloud computing에서 DoS 공격을 방어하기 위한 효과적이고 혁신적인 방법임을 증명했다.

링 마우스 : 손가락 움직임에 의한 컴퓨터 무선 입력 장치

Phan, Ke Hien 한국산업기술대학교 일반대학원 2018 국내석사

국문요약 링 마우스: 손가락 움직임에 의한 컴퓨터 무선 입력 장치 한국산업기술대학교 일반대학원 전자공학과: 판게히엔 지도교수: 정 두 희 이 논문에서는 링과 같이 손가락으로 감싸는 컴퓨터 용 무선 장치를 연구했습니다. Ring Mouse는 Bluetooth를 통해 컴퓨터에 무선으로 연결된 마우스 역할을하는 스마트 장치입니다. 손가락 움직임으로 컴퓨터의 마우스 커서를 제어 할 수 있습니다. 마이크로 컨트롤러 Cortex M4와 함께 nRF52832를 사용함으로써 우리는 전력 효율이 높고 비용 효율적인 회로를 만들었습니다. 모션 데이터는 MPU-9250 모듈을 사용하여 획득합니다. 장치의 기계적 케이스는 3D 인쇄 기술로 설계 및 제작되었습니다. ABSTRACT Ring Mouse: A Wireless Input Device for Computers by Finger Motions By Phan Ke Hien Advisor: Professor Jung Doo Hee Course for Electronics Engineering Graduate School Korea Polytechnic University In this thesis, we studied a wireless device for the computer which is carried on the finger like a ring. Ring Mouse is a smart device that acts as a mouse that is connected wirelessly to a computer via Bluetooth. One can control the mouse cursor on the computer with finger motions. By using nRF52832 with microcontroller Cortex M4, we made a circuit that is power-efficient and cost-effective. Motion data is acquired by using an MPU-9250 module. The mechanical case of the device is designed and made by 3D printing technologies.

A study on AR- Based interactive Design Applications for Supporting Integrated Architectural Design : 통합건축 설계 프로세스 지원을 위한 증강현실 기반 인터랙티브 디자인의 활용에 관한 연구

Phan, Viet Toan 경북대학교 대학원 2011 국내박사

In recent years, the information technology (IT) in architecture has been achieved numerous remarkable advances. These advances also contribute to development of Computer-Aided Architectural Design (CAAD) field. Currently, whole design tools became indispensable for supporting architects, engineers, technicians, et al in their works. Especially, the current Building Information Modeling (BIM) concept is fascinating architects and other specialists by Integrated Design Process (IDP), which are considered as the novel design process. The IDP is expected to be replaceable for conventional design process in architecture. However, the current design platform allows users to design and manage their project models in the absolute virtual environment, and then this problem seems to be isolation of design platform from IT advances of CAAD. In 10 years recently, Augmented Reality technology (usual abbreviation as AR) have been proving as an interest and full applicable technology in many fields, e.g manufacture& engineering, medical, commercial, military, entertainment, et al. The AR can create up a novel working environment that its term is within Mixed Reality (MR) spectrum (Milgram 1994) [12] . Along with AR, the virtual model can be posited in real environment, and then users are able to observe and interact with virtual model in real-time. It means that the user still keeps his perception about a real environment while he is working with virtual objects. Hence, this research aims to study on using AR technology as such an assistance tools for current architectural design works. This research proposes and demonstrates the AR-based interactive design approach, which can assist architects and engineers to observe and interact with BIM models in the phases of integrated architectural design process. Therein, the collaborative working method within AR interface could be recognized as the supplement activity in integrated design process. By AR interactive design approach, the architects and designers can gather clearly more knowledge about information integrating of BIM models. Furthermore, it also enable users contribute and share their design content easily in early stages of integrated design process. The AR operations will rely on the computer vision- based AR tracking. Thereat, the AR implementations will be built basing on usage of the open ARToolKit library, which was known as the popular one for developing many AR applications on the world. Plus, the practical applications are illustrated for some specific usage scenarios of integrated design concept. In these prototypes, the AR working system acts the role as the useful device, which can support the interactive and collaborative working environment for architects or designers. Those are the practical implementations in some kinds of architectural works, such as: real-time discussion for interior design, AR collaborative urban design and real-time crosscheck for technical component on site. By those outcomes, we expect that AR interactive design will become the realizable and useful approach for supporting integrated architectural design process, and even more in the future works of architecture and construction.

Optimized Offset Algorithm for Pockets with Islands Using Vertex Offset=

Phan Thi Thu Thuy 전남대학교 대학원 2008 국내석사

The offset edge algorithm is a common method for creating contour-parallel paths and has been widely studied. The method includes approaches such as a pair-wise intersection and Voronoi diagram. Different from these approaches, the method proposed in this paper discerns an optimized offset algorithm via the offset vertex and includes four steps as follows. (1) The offset vertices are computed based on bisectors (line-segment, line segment); (2) the validity of combining the direction and position checking for each offset edge is the main point of the proposed paper; (3) an efficient algorithm is constructed to connect all offset edges simultaneously to generate raw offset lines without local invalid loops; and (4) the offset-distance check is performed to remove the global invalid loops from the raw offset lines as well as interference loops in joining boundaries and multiple islands. The proposed method is verified with various slice contour shapes, with or without islands, and good results were obtained for significant reductions in the calculation time. 옵셋 에지 알고리즘은 평행하게 외곽 경로를 순차적 옵셋으로 생성하는 일반적인 방법이고 폭넓게 연구되어 지고 있다. 이 알고리즘은 Pair-Wise Intersection과 Voronoi diagram과 유사한 접근방법이다. 본 논문에서 제시한 방법과의 차이는 다음과 같이 4가지로 요약할 수 있다. (1) 옵셋 점들은 Line-Segment의 이등분선을 이용하여 계산한다. (2) 각 옵셋된 에지들에 대한 방향 및 위치를 체크하여 옵셋된 에지들의 타당성을 체크한다. (3) 효율적인 알고리즘을 위해 유효하지 않는 로컬 루프가 없는 옵셋된 라인들을 실시간으로 연결하여 옵셋라인을 생성한다. (4) 옵셋거리체크를 이용하여 중첩된 옵셋 라인 및 유효하지 않는 글로벌 루프를 제거한다. 본 논문에서 제안한 방법은 다양한 단면 형상에 대하여 검증을 하였으며 상당한 계산시간의 단축을 얻었다.

Electronic devices based-on the integration of mixed-dimensional van der waals heterostructures

Phan, Thanh Luan Sungkyunkwan university 2020 국내박사

Physical device scaling of traditional silicon metal-oxide-semiconductor field-effect transistors (MOSFETs) has driven progress in computing for decades; however, continued scaling is become increasingly difficult. Consequently, there is a need for minimiture the integrated circuit beyond-silicon nanotechnologies. Besides, ever since the discovery of carbon nanotube (CNT), graphene and transition metal dichalcogenide (TMD), 1D-2D layered materials as the platforms for exploiting the extraordinary properties in the low-dimensional physics. Owing to their small diameter (CNT), thin, flat and a dangling-bond-free surface, which will interact each other through van der Waals (vdW) forces and promise an order-of-magnitude improvement in device performance. However, it remains a challenge to produce the vertical configuration of mix-dimensional heterostructures over large-scale areas with high quality. In particular, graphene electrode cannot perform as below 10 nm scaled electrodes due to the band gap opening in graphene nanoribbon. Together, graphene electrode in vertical-field-effect-transistor (VFET), which possess the screening effect by the bottom gate-induced modulation, resulting to low on/off current ratio. On the other hand, CNT is commercialized materials with small range of diameter (1-2 nm), which is not only increasing the number of devices in the integrated circuit but also can enhance the device performance owing to low screening effect. In this dissertation, the systematically study the screening effect on VFET was discussed, while also highlight the improving the device scaling limits of integration circuits. In Chapter 1, 1D-2D materials structures and properties are briefly reviewed. In chapter 2, the screening effect was systematically study with CNT (1D)/MoS2 (2D) VFET. In this topic, a screening-engineered CNT network/MoS2/metal heterojunction CNT-VFET is fabricated for an efficient gate modulation independent of the drain voltage. In Chapter 3, for further increasing the number of devices in future integrated circuit, we proposed and demonstrated the vertical memristor by constructing the CNT (1D) and single molecule (0D). In chapter 4, we systematically study the screening effect on the interface-doped between ZnO /others oxide heterojunctions. Finally, the perspectives from my personal point of view in vdW heterostructure are covered by the Chapter 5.

Control strategy for quadruped robot with articulated spine

Phan, Luong Tin Sungkyunkwan university 2020 국내박사

This thesis presents the development of the control strategy for quadruped robot with articulated. The research focuses on analyzing and controlling a multi-body quadruped system with an articulated spine and compliant legs as well as providing the tools to study a multi-body, articulated quadrupedal robot. The research has been systematically accomplished through several steps and can be addressed as follows. First, a survey on the development of recent quadruped robots with spine is introduced in chapter 1. The objectives of the research and the motivation have also been stated. Second, chapter 2 is the study on two-segmeted leg and the implementation of its running motion. The leg model is inspired by the human leg. An energy approach is used to identify the characteristics of the model and run the optimization to obtain dynamic and mechanical parameters for stable running locomotion. Then the real leg robot is built and validated in the experiments. Third, chapter 3 describes the investigations on spinal joint effects on running locomotion of multi-body quadruped robot. There are two quadruped robot with/without an articulated spine have been modeled and studied for highly dynamic locomotion. Both models have two-segment legs with mass and inertia to be closer to the real robot. The joints are compliant joint with spring and damper to simulated the SEA-type actuators in the real robots. The optimization and simulation of the running are discussed here. Then the analysis on the effects of spinal joint and its location is presented as well as suggested to choose the proper location for placing the spinal joint on the robot body. Fourth, the development of the quadruped robot with articulated spine and compliant leg named AIDIN-IVS is described in Chapter 4. This chapter realizes all the studied have done in the previous chapters to build the hardware and propose a hierarchical controller method to help robot perform the highly dynamic locomotion.

카페 모바일 앱의 서비스편의성이 재이용 의도에 미치는 영향 : 지각된 가치 매개효과와 신뢰의 조절효과

PHAN THI THUY DIEM 가천대학교 대학원 2019 국내석사

국문초록 모바일 앱의 이용의 증가는 최근 개인 소득의 증가와 라이프 스타일의 변화로 자신의 실생활에 있어서 자신에게 도움이 되는 편의성을 추구하는 하나의 현상으로 볼 수 있다. 특히 최근 소비자들의 소비 형태를 살펴보면 시간과 노력을 줄일 수 있는 편리성을 추구하는 경향을 볼 수 있다. 모바일 앱에 관한 기존의 연구들은 모바일 앱의 기술적 차원이나 정책적 차원의 연구에 집중되어 모바일 앱 이용자들의 특성이나 이용형태 및 지각된 가치에 대한 연구는 미흡하며 특히 모바일 앱 이용 후 행동에 대한 연구는 초창기 단계이다. 또는 모바일 앱 시장의 활성화에 따른 시장의 변화를 고려하여 기존 서비스품질보다는 고객이 구매하고 이용하는데 있어서 강한 영향력을 주는 서비스편의성의 개념을 통해 보다 현실적으로 검증 필요하다. 이에 따라 본 연구는 카페 모바일 앱 이용자들을 대상으로 서비스편의성, 지각된 가치 및 재이용 의도와의 관계에 대해 인과관계, 서비스편의성과 지각된 가치의 관계에 있어 신뢰의 조절역할을 파악하였다. 독립변수로 카페 모바일 앱의 서비스편의성을 선정하였으며, 지각된 가치를 매개 변수로 그리고 재이용 의도를 결과변수로 선정하여 실증 분석하였다. 본 연구에서는 선행연구의 이론적 연구와 검토를 토대로 연구모형과 가설을 설정하고 최근 6개월 이내 카페 모바일 앱 이용자를 대상으로 자료를 수집하여 SPSS 22.0 통계 프로그램을 이용하여 실증분석을 실행하였다. 연구가설을 검증한 결과를 통해 고객의 지각된 가치를 이끌기 위해서는 카페 앱의 서비스편의성 향상이 선행되어야 한다는 그리고 지각된 가치를 매개로 재이용 의도를 이끌 수 있다는 연구결과를 제공했다는 점에 실무적인 의의를 찾을 수 있다. 이와 같은 연구 결과를 토대로 카페 모바일 앱 고객에게 서비스편의성이 우수하게 지각되면 모바일 앱의 이용가치가 향상 된다는 점에서 고객이 지각하는 서비스편의성에 대해 더욱 많은 노력을 기울여야 할 것이다. 카페 모바일 앱 이용자가 앱을 재이용하여 카페의 충성고객이 되기 위해서는 고객 가치를 제공이 선행되어야 한다는 점을 시사한다. 본 논문은 서론에서 결론까지 총 5장으로 구성되어있다. 제 1장은 본 논문을 연구하게 된 배경과 필요성, 목적 및 방법 체계 등 구성하였다. 제 2장은 이론적 배경과 선행연구의 고찰로서 학문적 근거를 이루는 부분으로 국내 및 국외의 선행연구를 연구하여 각 요인의 개념과 선행연구자들의 연구내용 및 주장을 중심으로 이론적인 지식습득과 응용까지 체계화된 내용을 기술하였다. 제 3장은 연구 설계 부분으로 연구가설 및 연구모형을 설정하기 위한 요인의 선정 근거를 이론적 배경 및 선행연구를 바탕으로 다양한 국내외 문헌을 분석하여 제시하였다. 제 4장은 실증적 분석으로서 표본의 특성, 기초통계 분석, 연구가설의 검증 등의 내용으로 구성하였다. 마지막으로 제 5장은 결론 부분으로서 본 논문의 연구결과를 정리하였으며, 연구의 의의와 향후연구 과제를 제시하였다. KEY WORDS: 카페 모바일 앱, 서비스편의성, 신뢰, 지각된 가치, 재이용 의도.