Redundancy optimization problems for systems with dependent failure rates

The present study is concerned with some redundancy optimization models for “load-sharing” devices. The models considered here enable one to examine the extent to which the optimal allocation of redundancies is affected if a model based on the assumption of mutual independence of components is used in situations where there is actual “load-sharing”.     

Challenges for giga-scale integration

The “giga-chip era” has begun. A new challenging approach to ULSI reliability is now greatly needed in response to the “paradigm shift” now being brought about by simple scaling limitations, increased process complexity, and diversified ULSI application to advanced multimedia and personal digital assistant (PDA) systems. A good example of this shift is the new movement from simple failure analysis by sampling the output of a manufacturing line to the “building-in-reliability” approach. To pursue this technique, greater importance will be attached to a deeper physical understanding of the significant relationships between the input variables and product reliability (including frequent use of Computer Aided Design, CAD and Design Automation, DA), and to total concurrent engineering from research labs to production sites. Furthermore, fast, new ULSI testing methods and new yield-enhancing redundancy techniques that reduce costs will be increasingly needed to achieve high reliability for ULSIs with 10⁹ devices on a single chip. Only with these approaches can we pave the way for giga-scale integration (GSI) in the 21st century.     

Generic qualification of semi-custom IC product families

The problem of verifying the integrity, and quantifying the reliability of semi-custom IC product families is addressed, and one possible approach to efficient “generic qualification” is outlined. The approach used relies on qualification via a set of chips specifically designed for this purpose, rather than via one or more “product” chips. Key features integrated into these test vehicles are that the entire “cell library” is represented, as well as that the “worst case” features are maximized.     

Ultra Wide Band WLANs: A Self-Configuring Resource Control Scheme for Accessing UWB Hot-Spots with QoS Guarantees

In the framework of wireless access networks the Hot-Spot concept is attracting several operators. In a Hot-Spot near stationary terminals may reach one or more Radio Access Points (RAP) offering wireless access to the fixed network. Mobile terminals should be able to register to the network, associate to a RAP and activate a wireless communication supporting given bit rates and Quality of Service (QoS) features. Several mobile users, requiring different services, enter and exit the Hot-Spot. In this scenario network operators should have the opportunity to configure quickly radio resources to serve the mobile terminals and to handle efficiently the network resources in order to maximize the income. Among the different technologies emerging in this field, we investigate the feasibility of a wireless access based on Ultra Wide Band (UWB) radio, combined with a flexible admission control scheme based on transmission power selection. We employ UWB in unlicensed mode, i.e., we operate in accordance to the limits imposed by the regulatory bodies (e.g., US Federal Communications Commission). The flexibility of the admission control depends mainly on the capability of a mobile terminal of “measuring” the environment it is entering and thus supporting the RAP in the selection of the appropriate transmission parameters. The proposed approach provides an admission policy based on the Maximum Extra Interference (MEI) and selects the power level through a simple interaction among the involved mobile terminals. The information for basing the decision on is collected through measurements and signaling. In order to increase the system efficiency, transmission parameters are selected in accordance to a “balancing” criterion (thus Balanced-MEI, B-MEI). The B-MEI approach keeps quite simple the admission of new mobile terminals in a RAP’s area but contemporarily satisfies the trade-off between fair resource assignment and system efficiency. This is a key trade-off in wireless access systems where interference effects determine the upper limit of the number of users that can be admitted in the network.Francesca Cuomo received her “Laurea” degree in Electrical and Electronic Engineering in 1993, magna cum laude, from the University of Rome “La Sapienza”, Italy. She earned the Ph.D. degree in Information and Communications Engineering in 1998, also from the University of Rome “La Sapienza.” Since 1996 she is an Assistant Professor at the INFOCOM Department of this University. Her main research interests focus on broadband integrated networks, Intelligent Networks, architectures and protocol for wireless networks, mobile and personal communications, Quality of Service guarantees and real time service support in the wired and wireless Internet.She participated in: (I) the European ACTS INSIGNIA project dedicated to the definition of an Integrated IN and B-ISDN network; (III) IST WHYLESS.COM project focusing on adoption of the Ultra Wide Band radio technology for the definition of an Open Mobile Access Network; (III) RAMON project, funded by the Italian Public Education Ministry, focused on the definition of a reconfigurable access module for mobile computing applications. She is now participating to the European IST ePerSpace Project focusing on the support of personalized audio/video services at home and everywhere. She is also involved in FIRB project VIRTUAL IMMERSIVE COMMUNICATIONS (VICOM) where she is responsible of the research activities on the BAN and PAN networks.Dr. Cuomo is in the editorial board of the Elsevier Computer Networks journal and she has served on technical program committees and reviewer in several international conferences and journals including ACM Wireless Mobile Internet Workshop, IEEE ICC and GLOBECOM, IEEE Trans. on Wireless Communications and IEEE Journal on Selected Areas on Communications.Cristina Martello received her Laurea degree in Electronic Engineering (magna cum laude) in July 2000 from Università di Roma “La Sapienza”. She earned the PhD degree in Information and Communications Engineering in February 2004 (Università di Roma “La Sapienza”).Since January 2001 she has been working in the IST European HYPERLINK “/” “_blank” Whyless.com project on an open mobile access network based on the Ultra Wide Band radio technology. She collaborated with HYPERLINK “http://www.coritel.it/” “_blank” Co.Ri.Tel. (a research consortium on Telecommunications) as a fellowship holder in 2000/2001 for the project SWAP on the feasibility of a re-configurable software module for the dynamic Radio Resource Control in the 3G of mobile wireless systems, and in 2002 for the project PRESTO.Her main research interests regard the developing of flexible and distributed Radio Resource Control techniques for “ad-hoc like” networking paradigms.     

Interresolution Look-up Table for Improved Spatial Magnification of Image

The most commonly used image magnification techniques are interpolation based: nearest neighbor, bilinear, and bicubic. The drawbacks of these traditional methods are that images magnified by the simple nearest neighbor method often appear “blocky,” while images magnified by linear and cubic interpolations usually appear “blurry.” In this work, a new technique, which improves the performance of the traditional image magnification methods, is presented. We show how a differential image pyramid is first constructed using traditional interpolation methods, then how a vector quantizer is designed using the pyramidal data. The vector quantizer is a look-up table, termed the interresolution look-up table (IRLUT), which uses the lower resolution image vector as input to find as its output the corresponding higher resolution image vector. The improved image is produced by using the IRLUT's outputs to compensate for the image magnified by the traditional methods. Experimental results which show that images generated by the current method have sharper edges as well as lower reconstruction mean-square errors than those produced by traditional methods are presented.     

Coding theorems on a generalized “useful” inaccuracy

Taneja and Tuteja proved a noiseless coding theorem by considering “useful” inaccuracy and “useful” mean codeword length. In this paper we consider a generalization of the “useful” mean codeword length and establish noiseless coding theorems by using this generalization.     

Reliability of networks of three-state devices

A three-state device is a device that can exhibit two different types of failure mode, an “open” failure and a “shorted” failure. This paper treats networks whose arcs may experience these two failure modes in addition to the normal “success” state. The network is undirected and has two designated nodes as source and sink. Such a network is itself subject to each of the two failure modes, and the reliability problem considered is computation of the probability of each of the three states of the network. Our observation is that such problems are easily reduced to the usual two-state network reliability problem for which common techniques such as the factoring theorem are readily applicable.     

Reliability of a focused ion beam repair on digital cmos circuits

The usefulness of FIB technology for device modification is commonly recognized in the industry. Yet, very little is known concerning the reliability of these circuit changes. This paper presents the reliability assessment of a “standard” FIB repair on digital CMOS circuits. The overall conclusion is positive : the lifetime of a “standard” FIB repair is found to be more than a few months, which is largely sufficient for prototyping.     

Unreliable queuing with repeated orders

The study of queuing models with repeated orders is motivated by new developments in telecommunication technology as the use of “repeat-last-number”, “auto-repeat”, “ring-back-when- free” and other facilities [31,38,40]. In this paper we focalise our attention in an important aspect: the influence of the reliability of the communication line on the distribution of the number A(t) of customers in the system.First we give a short review of studies in this area. Next, we consider a version of the unreliable M/G/1/1 queue with repeated orders. The distribution of the non-markovian jump-process A(t), t≥0 is studed by an adequate “markovization”. We obtain a generalization of the Pollaczek-Khintchin-Alexandrov formula     

Fuzzy measure of complex system outages

In recent years, the planning and operation of complex systems has involved many uncertainties. More probabilistic concepts are available for complex modelling problems, where all uncertainties are treated in a probabilistic way. There are some statements in complex systems modelling problems which are not treated or viewed in a probabilistic way. A power system example is considered because of its high complexity, owing to the uncertain operation of the system. For example, a statement such as “the available reserve capacity is very large and the present demand is average”, used in the operation of power systems, is very imprecise. Subjective terms are used to characterize the above statement. The terms “large” and “average” are called linguistic variables. These subjective terms are well modelled by fuzzy sets. As an illustration, fuzzy concepts are applied to measure power generation system outages.     

Dual phase probing technique for IC-internal failure analysis

New electron beam probing techniques have been developed which are based on either the subtraction of two stroboscopic phases at two test vectors during the recording of a single image, or the probing of two phases at a single physical point of interest. These are, respectively, the image-based dual phase image, and the point-probing-based dual phase measurement. These new techniques are perfect for IC-internal failure analysis as they enable the detection of “opens” and “stuck-at” errors and can be linked to fault simulation software and a fault dictionary.     

Adhoc-like routing in wired networks with genetic algorithms

Routing of packets in networks requires that a path be selected either dynamically while the packets are being forwarded, or statically (in advance) as in source routing from a source node to a destination. Quality of service (QoS) driven routing has been proposed using a protocol called the “Cognitive Packet Network” (CPN) which dynamically selects paths through a store and forward packet network so as to provide best effort QoS to route peer-to-peer connections. CPN operates very much as an adhoc protocol within a wired setting, and uses smart packets to select routes based on QoS requirements. We extend the path discovery process in CPN to include a genetic algorithm which can help discover new paths that may not have been discovered by smart packets. We describe how possible routes can “evolve” from prior knowledge, and then be selected based on “fitness” with respect to QoS. We detail the design of the algorithm and of its implementation, and report on resulting QoS measurements.     

Three-dimensional signal processing for full utilization of NTSC signals and transmission capacities

Three-dimensional (3D) signal processing for TV signals and its applications to higher-picture-quality TV systems are described. Here, “3D” implies “horizontal-vertical-temporal”. The main applications mentioned in this paper are 3D signal processing schemes in ATV (Advanced TV), such as IDTV (ImproveD TV) and EDTV (EnhanceD/Extended Definition TV). In IDTV, proscan conversion is described as the interpolation of 3D sampling, and 3D YC separation as demodulation of 3D modulation. In EDTV, the high-resolution Y component is multiplexed into the “Hole” an inefficiently used space in the 3D frequency domain, by modulating a 3D subcarrier.     

Optimum allocation of computer spares for three-level stocks

This paper presents a model for determining the optimum stock in a three level depots system. The method for determining stock levels uses “incremental performance per price algorithm” (IPPA) and the “new Lawler-Bell algorithm” (NLB). The practical calculation is carried out on a computer, the results being presented in the form of a list of necessary spare units from the first to the third level.     

Semiconductor device reliability vs process quality

This paper describes a method for defining a quantitative model relating “quality” expressed in terms of parameter distributions and “reliability” expressed in terms of failure rates. This model makes it possible to generate a more realistic failure rate estimate for semiconductor devices. With this model, failure rate predictions based on conventional life test data and on process parameter distributions, can be defined.     

Microelectronics'' and reliability''s new tool: UNIX today

Today's quality paradigms deal with a very broad array of concepts and approaches. This paper describes these in detail. No longer is quality the “policeman”, but now a needed “team player”. It is important that all concerned understand and apply these new tools.     

Fixed-width confidence interval estimation of the inverse coefficient of variation in a normal population

A sequential procedure is developed in order to construct a confidence interval of “fixed-width and preassigned coverage probability” for the inverse of the coefficient of variation of a normal population. The proposed sequential procedure is proved to be “asymptotically efficient and consistent” in the sense of Chow and Robbins ([1]: Ann. Math. Statist. 36, 457–462 (1965)). Asymptotic distribution of the stopping time is derived.     

Throughput Analysis and Admission Control for IEEE 802.11a

We propose a new Markov model for the distributed coordination function (DCF) of IEEE 802.11. The model incorporates carrier sense, non-saturated traffic and SNR, for both basic and RTS/CTS access mechanisms. Analysis of the model shows that the throughput first increases, and then decreases with the number of active stations, suggesting the need for an admission control mechanism.We introduce such a mechanism, which tries to maximize the throughput while maintaining a fair allocation. The maximum achievable throughput is tracked by the mechanism as the number of active stations increases. An extensive performance analysis shows that the mechanism provides significant improvements.Mustafa Ergen received the B.S. degree in electrical engineering from Middle East Technical University (METU) and was the METU Valedictorian in 2000. He received the M.S. and Ph.D. degrees in electrical engineering in 2002 and 2004, the MOT certificate of HAAS Business School in 2003, and the M.A. degree in International and Area Studies in 2004 from the University of California, Berkeley.Dr. Ergen has been conducting research in wireless communication networks with an emphasis on sensor networks, wireless LAN and OFDM systems and is the author of many works in the field, including the book (with A.R.S. Bahai and B.R. Saltzberg) Multi-Carrier Digital Communications: Theory and Applications of OFDM (New York: Springer, 2004).He is National Semiconductor Post Doctoral Fellow and was awarded eight times Bulent Kerim Altay Award by department of electrical engineering in METU and received Best Student Paper Award in IEEE ISCC 2003 and has an invited paper in IEEE GLOBECOM CAMAD 200.Pravin Varaiya is Nortel Networks Distinguished Professor in the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley. From 1975 to 1992, he was also Professor of Economics at Berkeley. His research is concerned with communication networks, transportation, and hybrid systems. He has taught at MIT and the Federal University of Rio de Janeiro, Varaiya has held a Guggenheim Fellowship and a Miller Research Professorship. He received an Honorary Doctorate from L’Institut National Polytechnique de Toulouse, and the Field Medal of the IEEE Control Systems Society. He is a Fellow of IEEE and a member of the National Academy of Engineering. He is on the editorial board of several journals, including “Discrete Event Dynamical Systems” and “Transportation Research-C.” He has co-authored three books and more than 250 technical papers. The second edition of “High-Performance Communication Networks” (with Jean Walrand) was published by Morgan-Kaufmann in 2000. “Structure and interpretation of signals and systems” (with Edward Lee) was published in 2002 by Addison-Wesley.     

Distributed control based on distributed electronic circuits: application to vibration control

This paper focuses on the design of distributed control related to distributed mechanical systems. The sensors and actuators are assumed to be numerous and periodically distributed. The problem addressed in this paper is: “Can we find a way to approximate an optimal control law with a distributed electronic circuit”. Solutions to this problem are proposed in the framework of vibration control using piezoelectric actuators and sensors.