ISSN 1556-6757


SJI 

 


 
 
 
Volume 1, Issue 1, 2007
 
 

An Autonomous Control Methodology for Real-Time Traffic Injection Control
Hsiu-Jy Ho, Wei-Ming Lin

Abstract
When traffic load approaches the capacity of a freeway, not only does the expected delay for motorists exponentially increases but also the overall throughput suffers dramatically. Engineers have thus started employing stoplights (ramp-meter) on access ramps to freeways in highly congested areas to control the traffic injection into the freeway in order to reduce the overall delay for the motorists. The goal of this paper is to develop a comprehensive Autonomous Real-time Traffic Injection Control system (ARTIC) capable of minimizing the overall delay for motorists according to the then traffic input load and freeway congestion situation without replying on any history data as all other known approaches do. We first propose a general methodology that provides an autonomous self-adjusting process to optimize performance for many real-time resource-sharing applications, the Autonomous Performance Optimizing Control Methodology (APOCoM). This methodology which ARTIC is based on can be used to automatically optimize performance of most resource-sharing system in real time through periodical self-adjustment of some system settings. Simulation results show that the system employing the ARTIC thus designed easily outperforms the system without using the control approach. In one of the simulation for daily twin-peak rush hours, about two fifth of congestion time (70 out of the original 167 minutes) is eliminated, and about one third of travel time (9 out of the 27 minutes) is saved per peak cycle. Full Article



Some Issues Related to Multi-Component Seismic Analysis of Steel Moment Frames

Alfredo Reyes-Salazar,  Arturo López-Barraza, Luis A. López-López, Juan I. Velázquez-Dimas

Abstract

Several issues regarding multi-components seismic response analysis of structures are addressed in this paper.  The first issue is related to the accuracy of the commonly used rules to estimate the combined effect of the individual components of earthquakes. The rules are studied for normal and principal components, for local and global response parameters, elastic and inelastic behavior and two and three components. The critical orientation of the components is identified.  The second issue threats with the relative magnitude of the effect of the vertical component with respect to those of the horizontal components.  Finally, the accuracy of estimating the effect of the weaker horizontal component (RY) as 85% of that of the stronger horizontal component (RX) is studied.  Results indicate that the total base shear is reasonable estimated by the rules.  However, they can underestimate the combined response in terms of axial loads for inelastic behavior. For the horizontal components the SRSS rule is, in general, less conservative than the 30% rule.  For the three components the 30% rule is less conservative.  It is concluded that if the percentile rule is used to estimate the combined response a value of 40% should be used instead of 30%.  It is also observed that the principal components give the maximum response and that the ratio of the effect of the vertical component to those of the horizontal components can be significant and consequently should explicitly be used in design.  Values larger than unity are observed in some cases.   Results also indicate that the ratio of the effect of the minor horizontal component to that of the major horizontal component is much smaller that the typical assumed value of 0.85.   The value obtained in this study is about 0.40.  Full Article



An Explicit Expression for the Break-Even Radius of Insulation on a Cylinder in Cross-Flow
Richard A. Davis
 

Abstract

An explicit expression was developed for approximating the break-even radius of insulation on a cylinder in cross flow with forced convective heat transfer where the heat transfer rate equals the heat transfer rate from a bare cylinder.  Similar assumptions for the classical form of the critical radius of insulation were invoked.  However, the assumption that the heat transfer coefficient is independent of the radius of insulation was relaxed.  The explicit expression derived here uses an algebraic approximation for the logarithmic-mean radius of insulation to avoid the computational inconvenience of solving the implicit nonlinear function of the break-even radius of insulation that is sensitive to initial guesses for the root.  The results of the approximation agree with the implicit expression within 1% and 5% for practical insulation thicknesses up to 15 and 25 times the radius of the bare cylinder, respectively.  An analytical expression for the critical radius of insulation where the convective heat transfer coefficient varies with radius of insulation is also included. Full Article



Idealized Plasma Problems for Magnetohydrodynamic Code Verification
Pavlos G. Mikellides
 

Abstract

The closed-form analytic solutions to two idealized plasma problems are presented as test cases for verification and benchmarking of magnetohydrodynamic computer codes. The first problem addresses magnetic diffusion with joule heating designed to produce a diverging temperature profile so as to significantly challenge the stability and accuracy limitations of different numerical schemes. The second problem is the classic magneto-shock tube problem for which an explicit analytic solution is derived. This allows a simple and unique presentation of the solution that can be easily utilized. A magnetohydrodynamic code is employed to model the problems and comparisons of the numerical results serve as bi-lateral validation of the analytic and numerical solutions. Furthermore, these comparisons serve as a reference standard for accuracy and overall code performance. Full Article


 

Development of an Energy-budget Snowmelt Updating Model for Incorporating Feedback from Snow Course Survey Measurements  Hamed Assaf
 

Abstract

A novel model for updating snowmelt estimates utilizing sparse, yet high quality snow course survey (SCS) measurements for the purpose of improving long term stream flow forecasts is presented. The paper provides details on the development of the mathematical scheme of the model from first principles of energy and mass balance of the snowpack. The development methodology represents a successful attempt at the challenging task of explicitly tying a complex daily highly nonlinear energy-budget snowmelt function to the irregular SCS measurements. The updating scheme facilitates the updating of sensitive snowmelt parameters that have a long-term seasonal impact on snowmelt runoff. The updating model is integrated within a river flow forecasting model, the UBC Watershed Model, for the purpose of improving seasonal stream runoffs. Preliminary application of the updating model shows significant improvements in both the snowpack and stream flow forecasts. Full Article


 

An Evaluation Methodology for Ambient Displays
Xiaobin Shen
 

Abstract

Unlike mainstream information visualization, ambient displays do not require active attention, which makes existing information visualization design and evaluation methodologies not readily applicable. In this paper, we present a new evaluation methodology for ambient displays. The methodology is then applied to a real-world case study, focusing on the effectiveness, efficiency, comprehension and distraction performance of four different visual cues for ambient displays. Our results show that the effectiveness factor order in ambient displays is animation, color, area and position. We also reveal how display-distraction influences the comprehension of ambient displays, and discuss a relationship between image change rate and data update rate. In addition, this paper proposes a measurement of efficiency from cognitive science and a quantified measurement of effectiveness in ambient displays. Finally, we propose four guidelines for ambient display design. Full Article



Performance and Emission Analysis of Bio Diesel Operated CI Engine
S.Sundarapandian  and
G.Devaradjane

Abstract
A theoretical model was developed to evaluate the performance characteristics, combustion parameters and emissions of vegetable oil esters like Jatropha, Mahua and Neem Oil esters. The predicted results of these fuels are compared with Experimental result of diesel fuel. From the results, it is found that the heat release and work done are reduced by about 4% for Jatropha, 5% for Mahua and 8% for Neem oil esters when compared to diesel. The harmful pollutants such as HC, CO, NOX and smoke are reduced in the vegetable oil esters compared to diesel fuel. From the investigation, it is concluded that the performance of vegetable oil esters are good. Thus the developed model is highly compatible for simulation work with bio diesel as an alternative fuel. Full Article


 

A New Approach for Constructing and Generating AOA Networks
Yuval Cohen, Arik Sadeh
 

Abstract

A significant drawback of Activities on Arcs (AOA) networks, is having several different possible networks describing the same project. In contrast, the Activities on Nodes (AON) representation is unique. Having both AOA and AON networks of a project is an advantage since some planning and optimisation techniques strictly require AOA format while others require AON format. While previous AOA research has been focusing on minimizing the number of dummy arcs, this paper focuses on generating a meaningful consistent network. Each AOA node in the proposed technique is related to a specific row in the immediate predecessors table: its incoming arcs represent the immediate predecessors, and its outgoing arcs represent the activity/ies possessing this set of precedence constraints. The proposed algorithm generates a unique AOA network from a list of precedence constraints. While it does not minimize the number of dummy arcs the efficiency in dummies is a by-product of this approach. Two equivalent mathematical expressions are developed for the number of generated AOA dummies of a given precedence table. The paper also presents some linear formulations that could be directly derived from an AOA net. The algorithm is explained through a detailed example that starts with an immediate predecessors table and ends with an AOA network. Full Article


 

Butterfly/Dragonfly – An Ambient Display of Stock Market Data
Keith V. Nesbitt, Robert Shen
 

Abstract

In the modern world of electronic data and global communication information displays can change quickly and so require constant attention from users. However, the nature of the modern world is also that users are often required to perform tasks in parallel and there may be competition for the user's attention. Ambient displays are information displays that are designed to function at the periphery of a user's attention. Unlike alarms, ambient displays should not interrupt a user from their current task. Changes in the display may, or may not be relevant to the user as the display is usually designed to show non-critical data. Because ambient displays are not critical to short term tasks, it may be difficult to develop a business case for using an ambient display. The questions that are most difficult to quantify are: "How to design a good ambient display?" and "When is an ambient display good?". This paper addresses these two questions by describing our research with a particular ambient display called; "Butterfly/Dragonfly". This display is designed to show stock market data and provide the user with short-term market trends for a particular stock. The application domain and implementation platform are described. The design of the specific display is described in the context of "good" design criteria. Finally a general framework for evaluating ambient displays is introduced and the preliminary results from an extended field trial are discussed. Full Article


 

A New Mesh Recognition Algorithm

A. Kazmierczak
 

Abstract

A rectangular mesh is a rectangular array of processors.  A new algorithm is presented to recognize a rectangular mesh. A program was written to determine if the new mesh recognition algorithm mesh is valid.  The program was written in C and tested using a representation of a network's nodes and their neighbors.  The program tests several meshes of different dimensions and different mesh-like structures.  The program found the meshes and rejected the non-meshes on the test data. The algorithm presented here is fairly simple and straightforward.  However, its true importance lies in the fact that it forms the foundation for algorithms for recognition of more complex mesh like structures, such as, ring mesh, torus, spheroid, ellipsoid, and 3-dimensional mesh. Full Article

 

Optimization Rules in DLV for the Bridge Crossing Problem
Sayan Ranu, Prabhakar Balakrishnan, G. M. Prabhu

Abstract

Three strategies to produce optimal solutions in Disjunctive Logic Programming for the well-known Bridge Crossing problem are described. These strategies are a piggyback strategy, a non-piggyback strategy, and a mixed strategy. An analysis to determine the number of actions required for an optimal solution using these strategies is also given. Conditions under which a particular strategy should be used to obtain an optimal solution are formulated and proved. The strategies are implemented in the form of optimization rules in a DLV program for the Bridge Crossing problem. Preliminary results indicate a drastic reduction in execution time when compared to other DLV programs for bridge crossing which do not incorporate these strategies. The implementation uses a DLV Java wrapper, which allows the embedding of disjunctive logic programs inside an object-oriented environment. Full  Article


 

Some Accepting Powers of Three-Dimensional Synchronized Alternating Turing Machines
Takao Ito, Makoto Sakamoto

Abstract

This paper introduces a three-dimensional synchronized alternating Turing machine (3-SATM), and investigates fundamental properties of 3-SATM0s whose input tapes are restricted to cubic ones. The main topics of this paper are: (1) a relationship between the accepting powers of 3-SATM0s and three-dimensional alternating Turing machines with small space bounds, (2) a relationship between the accepting powers of five-way and six-way 3-SATM0s, (3) a relationship between the accepting powers of 3-SATM0s and three-dimensional nondeterministic Turing machines Full Article


 

A Simulated Annealing Based Approach for ATM Network Optimization
Susmi Routray, A. M. Sherry, B. V. R. Reddy
 

Abstract

The increasing importance of telecommunications for applications such as the internet and video on demand leads to a requirement for a high bandwidth network such as Asynchronous Transfer Mode (ATM). The design of an optimal ATM network is a complex comprehensive task. Some of the problem domains are the topology, connectivity and routing decisions. Given the complexity of ATM design problem, computer based network design tools can be very effective in solving such type of problem. The important aspect of design tool is the usage of meta-heuristics as the optimization algorithm. Large scale optimization problems comprise of many local maxima and minima, moving out of local minima are very important to get global

optima. ATM network design being a large scale optimization problem simple heuristics alone are not sufficient enough to solve the problem. This paper explores an ATM network design tool based on Simulated Annealing (SA). A new solution has been proposed based on SA that minimizes the cost of fiber ducts and installs a minimum net present cost PON (Passive Optical Network) ATM that satisfies the customer demand criterion. A comprehensive ATM design tool has been proposed in which the backbone network is connected using ring topology and the end-user connectivity is provided using star topology. Full Article



Comparison of hardware implementation and power consumption of low-power multiple output linear feedback shift register linear feedback shift register
Shilesh Malliyoor and Chao You

Abstract
A linear feedback shift register has a variety of applications. Various low-power architectures have been proposed. This paper compares two low-power multiple output architectures in terms of the hardware implementation and power consumption. A way to overcome the race around condition in these architectures, which will improve the architecture, is proposed. The polynomials are implemented by using 0.13 μm BiCMOS technology provided by IBM. This paper will also show that the improved Katti’s architecture, described in this paper is more power efficient than the improved Lowy’s architecture. In specific applications, such as E0 stream cipher, the efficiency can be as high as 83% for certain polynomials.  Full Article