Leif Olsson

Bit-Width Constrained Memory Hierarchy Optimization for Real-Time Video Systems

The great variety of pixel dynamics of real-time video-processing systems (RTVPS), ranging from color, grayscale, or binary pixels, means that a careful design and specification of bit widths is required. It is obvious that the bit-width specification will affect the total memory storage requirement. However, what is not so obvious is that the bit-width specification will also affect the design of the memory hierarchy, an impact similar for both hardware and software implementations. We have developed an integer-nonlinear-program formulation for the optimization of the memory hierarchy of RTVPS. An active surveillance video camera is introduced as a test case. We demonstrate how the optimization model can reduce the on-chip memory storage by 61% compared to a nonoptimal memory hierarchy

Strategic Proactive Obsolescence Management Model

When there is a demand larger than the corresponding number of components in stock, obsolescence problems may occur for those systems with a life cycle longer than that of one or more of their components, such as automotive, avionics, military application, etc. This paper discusses the electronic component obsolescence problem and presents a formal mathematical strategic proactive obsolescence management model for long life-cycle systems. The model presented in this paper utilizes redesign and last-time-buy (LTB) as two management methods. The LTB cost is estimated by unit cost, demand quantities, buffer, discount rate, and holding cost. Redesign cost is associated with component type and quantities. This model can estimate the minimum management costs for a system with different architectures. It consists of two parts. The first is to generate a graph, which is in the form of an obsolescence management diagram. A segments table containing the data of this diagram is calculated and prepared for optimization at a second step. The second part is to find the minimum cost for system obsolescence management. Mixed integer linear programming is used to calculate the minimum management cost and schedule. The model is open sourced allowing other research groups to freely download and modify it. A display and control system case study is shown to apply this model practically. A reactive manner is presented as a comparison. The result of the strategic proactive management model shows significant cost avoidance compared to the reactive manner.

Optimization of memory allocation for real-time video processing on FPGA

We present an optimization model for the allocation of shift registers to dual ported FPGA memory blocks. Shift registers are used in real-time video processing for the storage of data flow dependencies. The model is formalized into a mixed integer linear program that can be executed using a general solver. Allocation results from realistic video systems verify the correctness of the model. This model serves as a formal specification and setup for the development of an efficient allocation heuristic.

Component obsolescence management model for long life cycle embedded system

This paper discusses the component obsolescence problem and presents a mathematic model for life cycle analysis of long life cycle embedded system maintenance. This model can estimate minimized management costs for different system architecture. Matlab is used to generate a graph and Lingo is used for linear programming. A simple CAN controller system case study is shown to apply this model. A minimized management cost and an optimized management time schedule are given as the result. The responses from the experiments of the model meet our expectation. Although the model has lots of simplifications and limitations, it can give management strategy guidance to the designers who suffer from component obsolescence problems.

Position Statement: Sustainable Information and Information Systems (SIIS)

In this position statement we provide our understanding of the relation between the IS field and the notion of sustainability, and present our focus through a characterization of the “sustainability research” construct. By doing so, we hope to contribute to the discourse on a clarification of the construct itself in our research community.

Estimation of a basal area growth model for individual trees in uneven-aged Caspian mixed species forests

The aim of this study was to estimate a basal area growth model for individual trees in uneven-aged Caspian forests. A survey was conducted in order to find a natural forest without any harvesting activities, a so called ‘untouched forest’ and an area was selected from the Iranian Caspian forest. Three sample plots in the same aspect and of the same forest type were selected. In each plot, total tree height, diameter at breast height, distance of neighbor trees and azimuth were measured. Thirty trees were selected and drilled with increment borer to determine the increment model. Regression analysis was used to estimate the growth model. Results show that, for individual trees, there is a significant nonlinear relationship between the annual basal area increment, as the dependent variable, and the basal area. The results also show that the basal area of competing trees has a positive influence on growth. That the increment is higher with more competing neighboring trees is possibly because plots with higher volume per hectare and more competition, most likely also have higher site index or better soil or better site productivity than the plot with lower volume per hectare.

Assessing the impact of the external non-discretionary factor on the performance of forest management units using DEA approach

ABSTRACT The purpose of this paper is to measure the relative performance of forest management units, and to analyze the impact of the external non-discretionary (ND) factors on these units’ technical efficiency. Toward this end, data envelopment analysis (DEA) technique in variable returns to scale environment with both discretionary and ND factors has been used. The required data are collected from 24 Iranian forest management units (as decision-making units (DMUs)) and included four inputs and two outputs. The ND factors are first ignored and it is shown that most of the forest management units are operating at high efficiency levels. Then the variable “area” is considered as the exogenously fixed (or the external ND) input in a modified ND model because it is outside of the forest manager’s control. The results indicate that the number of efficient units and the average technical efficiency score are reduced to 12 (approximately 50%) and 0.85, respectively. The forest management units should therefore increase their average efficiency score by 0.15 to move onto the new efficient frontier which is made by applying this strict criterion. As a consequence, it is recommended to apply the ND models for controlling the exogenously fixed factors and carrying out a correct and accurate evaluation, because the traditional DEA approaches may overestimate the efficiency of DMUs.

Optimization of raw material procurement at pulp or paper mills: the influence of weather-related risks

There are usually many sources for the supply of raw material to a pulp or paper mill in Sweden. Optimization of this supply is therefore a challenging task, and can only be managed properly if all aspects of risk are considered. In our study, these risks are related to when the weather reduces the load-bearing capacity of the ground or the roads. A stochastic and a deterministic model have been formulated, and they have been solved with mixed-integer quadratic programming and tested with data from a Swedish forest company. The results of this study show that the option value is greater than zero and that both the optimal policy and the option value change whenever the storage cost is altered. This shows that the optimal planning policy obtained from the stochastic model differs from the solution of the deterministic model.

Analyzing the Implications of Design Choices in Existing Simulation-Games for Critical Infrastructure Resilience

A literature study has identified the major impacts of important design choices in simulation models and simulation-games that model critical infrastructure resilience. The four major groups of design choices discussed in this article are: (1) the chosen learning goal (system understanding or collaboration training), (2) realism and time scale of the scenario, (3) design of player roles and communication rules, (4) number of action alternatives, replay-ability and richness of performance feedback while playing. Researchers and practitioners who build simulation-games for studying critical infrastructure resilience can use the accumulated insights on these four aspects to improve the quality of their game design and the quality of the simulation models the game participants interact with.