Paolo Gubian

A conceptual model for design management

Abstract Design management is a very important topic for every state-of-the-art cad / cae environment. By definition, the concept of design management addresses a set of functions which build, maintain, display, manage and enforce relationships among the data and among the design tools that are involved in a project. From this definition, straightforward user and functional requirements are derived. Then, a model which fulfils many of the requirements, especially in the data management part, is described. All the considerations are free from implementation details, so that modelling topics are not confused with programming problems. Our analysis is mapped on electronic hardware design; most of the concepts, however, are valid also in many other engineering fields.

SIMbrush: an open source tool for GSM and UMTS forensics analysis

The aim of this paper is to describe a new open source tool, usable on Windows and Linux platform, for digital evidence extraction from SIMs and USIMs card. Nowadays, closed-source or confidential tools are used for this purpose and this is contrary to Dauberts test, because, it is not possible to gain the high degree of acceptability from scientific community required by the test itself. This tool is being proposed, therefore, as a platform for the exchange of ideas, to constitute, free from the logic of copyright, a wide agreement. Security features of SIMs hamper in many ways the possibility to dump a bit for bit internal memory image. As a consequence, this tool interfaces itself to SIM cards in the standard way. Data is acquired in raw format (binary data) and represents digital evidence; interpretation of these raw data at a higher level of abstraction could be the purpose of an extension of this tool aimed at examination of the digital evidence.

Data Hiding in SIM/USIM Cards: A Steganographic Approach

The aim of this paper is twofold. First, the real structure of a SIM/USIM card file system will be presented, analyzing what is valuable from a forensics perspective and showing what evidence is not detectable and extractable with the tools present in the arena of open-source and proprietary software. After that, the paper will focus on a framework that can be used to detect and extract the so-called nonstandard part of a SIM/USIM file system, which is a concealed part usable also to store arbitrary and sensitive information. As a pro of-of-concept, an interesting example will be presented on the methods usable to obtain the data hiding in an ordinary SIM/USIM card

Approximate radial basis function neural networks (RBFNN) to learn smooth relations from noisy data

In this paper a novel RBFNN scheme is presented introducing the idea of strongly delocalized neural receptive fields. Based on delocalization, a robust deterministic annealing procedure is proposed for determining the RBF centers. It is shown that highly overlapped receptive fields exhibit good noise rejection capability. A real world sensor application of this RBFNN is described. By approximating the exact gaussian fields with a suitable radial function (RF), the forward step of the RBFNN can be efficiently implemented in a single digital chip for real time sensor applications.

Symbian Forensics: An Overview

This paper aims at unveiling the real and complete structure of the Symbian S60 v3 (third edition) platform filesystem, which is considered one of the most secure and armored systems issued by Symbian Ltd. in the last two years. By analyzing the unique features of security, which have been applied at the filesystem level, it will become clear how to develop applications for digital forensic purposes. Moreover, the limitations and main issues related to accessing the observable portion of the filesystem will be pointed out, and possible solutions will be presented.

Multiparameter time-domain sensitivity computation

In this paper, a novel approach for the computation of multiparameter time-domain sensitivity during circuit simulation is presented. The computation of the sensitivity values of one or more circuit variables (e.g., node voltages or branch currents) with respect to both design parameters (e.g., R, C, MOS length, MOS width...) and process parameters (e.g., tox, nsub, u0...) is addressed by introducing a rigorous mathematical derivation of the proposed direct differentiation modified algorithm (DDMA). First, the circuit interpretation of the analytical formulas as well as their theoretical derivation from the Tellegens theorem is discussed. Then, DDMA is compared with the direct method and the adjoint technique to emphasize the cost difference in terms of CPU operations. The accuracy of the new algorithm is also evaluated, by estimating the numerical error involved in the solution of discretized sensitivity equations. Finally, a set of circuit examples is presented to demonstrate the effectiveness of DDMA together with the implementation details needed to include the present sensitivity analysis in a circuit simulator such as Spice3F5.

Stability properties of integration methods in SPICE transient analysis

Experimental evidence shows that the usage of MOS transistor charge-control models in the SPICE circuit simulator may cause trouble in transient analysis, independent of the dimensions of the circuits. If the trapezoidal integration method is adopted for the branch currents computation of an MOS circuit in transient analysis, the solution sometimes oscillates indefinitely, alternating a positive error and a negative error at each SPICE internal time point. Device models and numerical algorithms have been taken into account in order to determine the causes of this behavior. The trapezoidal method has been identified as the main factor responsible for wrong outputs while Gear methods recover from errors in a finite number of steps.<<ETX>>

Transient sensitivity computation in circuit simulation

A new method for computing time domain sensitivity concurrently in time with the circuit simulation is proposed in this paper. First we present the mathematical derivation of this approach which simultaneously provides the sensitivity of one circuit variable with respect to all the design parameters. Then, we discuss its advantages with respect to the well-know direct techniques, comparing their cost equations in terms of CPU expensive operations. Finally practical issues to include the proposed analysis in a Spice-like simulator are addressed by means of an explanatory example. Results confirm the accuracy of our implementation.

Design management additions to the Octtools environment

Research is presented whose aim is to endow the Octtools environment with a set of design management (DM) functionalities. Two fields needing intervention have been isolated, i.e. task distribution among designers and design methodologies. The main lines of the approach are described: DM objects are stored in the same format as design objects and DM functions use OCT procedures to access them. Some difficulties pertinent to the control of the adherence to valid methodologies are given.<<ETX>>

Fundamentals on design management systems development

Some of the most important requirements of design management, as it is applied to an engineering environment in which semicustom IC design is produced, are detailed. Requirements are expressed in a way suitable for conversion into software specifications. A simple model which tries to fulfil most of these requirements is also presented. A detailed account of the requirements is given from the user point of view. The list of requirements is then interpreted with basic framework in mind.<<ETX>>