Illinois Institute of Technology

About: Illinois Institute of Technology is a education organization based out in Chicago, Illinois, United States. It is known for research contribution in the topics: Electric power system & Wireless network. The organization has 10188 authors who have published 21062 publications receiving 554178 citations. The organization is also known as: IIT & Illinois Tech.

Security Challenges for the Public Cloud

Abstract: Cloud computing represents today's most exciting computing paradigm shift in information technology. However, security and privacy are perceived as primary obstacles to its wide adoption. Here, the authors outline several critical security challenges and motivate further investigation of security solutions for a trustworthy public cloud environment.

Microfibrillar structure of type I collagen in situ

Abstract: The fibrous collagens are ubiquitous in animals and form the structural basis of all mammalian connective tissues, including those of the heart, vasculature, skin, cornea, bones, and tendons. However, in comparison with what is known of their production, turnover and physiological structure, very little is understood regarding the three-dimensional arrangement of collagen molecules in naturally occurring fibrils. This knowledge may provide insight into key biological processes such as fibrillo-genesis and tissue remodeling and into diseases such as heart disease and cancer. Here we present a crystallographic determination of the collagen type I supermolecular structure, where the molecular conformation of each collagen segment found within the naturally occurring crystallographic unit cell has been defined (P1, a ≈ 40.0 A, b ≈ 27.0 A, c ≈ 678 A, α ≈ 89.2°, β ≈ 94.6°, γ ≈ 105.6°; reflections: 414, overlapping, 232, and nonoverlapping, 182; resolution, 5.16 A axial and 11.1 A equatorial). This structure shows that the molecular packing topology of the collagen molecule is such that packing neighbors are arranged to form a supertwisted (discontinuous) right-handed microfibril that interdigitates with neighboring microfibrils. This interdigitation establishes the crystallographic superlattice, which is formed of quasihexagonally packed collagen molecules. In addition, the molecular packing structure of collagen shown here provides information concerning the potential modes of action of two prominent molecules involved in human health and disease: decorin and the Matrix Metallo-Proteinase (MMP) collagenase.

Stochastic Security-Constrained Unit Commitment

Abstract: This paper presents a stochastic model for the long-term solution of security-constrained unit commitment (SCUC). The proposed approach could be used by vertically integrated utilities as well as the ISOs in electricity markets. In this model, random disturbances, such as outages of generation units and transmission lines as well as load forecasting inaccuracies, are modeled as scenario trees using the Monte Carlo simulation method. For dual optimization, coupling constraints among scenarios are relaxed and the optimization problem is decomposed into deterministic long-term SCUC subproblems. For each deterministic long-term SCUC, resource constraints represent fuel and emission constraints (in the case of vertically integrated utilities) and energy constraints (in the case of electricity markets). Lagrangian relaxation is used to decompose subproblems with long-term SCUC into tractable short-term MIP-based SCUC subproblems without resource constraints. Accordingly, penalty prices (Lagrangian multipliers) are signals to coordinate the master problem and small-scale subproblems. Computational requirements for solving scenario-based optimization models depend on the number of scenarios in which the objective is to minimize the weighted-average generation cost over the entire scenario tree. In large scale applications, the scenario reduction method is introduced for enhancing a tradeoff between calculation speed and accuracy of long-term SCUC solution. Numerical simulations indicate the effectiveness of the proposed approach for solving the stochastic security-constrained unit commitment

Constant power loads and negative impedance instability in automotive systems: definition, modeling, stability, and control of power electronic converters and motor drives

Abstract: Power electronic converters and electric motor drives are being put into use at an increasingly rapid rate in advanced automobiles. However, the new advanced automotive electrical systems employ multivoltage level hybrid ac and dc as well as electromechanical systems that have unique characteristics, dynamics, and stability problems that are not well understood due to the nonlinearity and time dependency of converters and because of their constant power characteristics. The purpose of this paper is to present an assessment of the negative impedance instability concept of the constant power loads (CPLs) in automotive power systems. The main focus of this paper is to analyze and propose design criteria of controllers for automotive converters/systems operating with CPLs. The proposed method is to devise a new comprehensive approach to the applications of power electronic converters and motor drives in advanced automotive systems. Sliding-mode and feedback linearization techniques along with large-signal phase plane analysis are presented as methods to analyze, control, and stabilize automotive converters/systems with CPLs