document

Recent and future contributions of Delft University of Technology to smart grids

Tang, J.M. (author), Vuik, C. (author), Witteveen, C. (author)

In this report, the recent and future contributions of experts and groups of Delft University of Technology (DUT) on the topic of smart grids (SG) are presented. This may provide guidelines on how DUT can contribute in current and future SG projects, such as the current TKI project on “Smart Grid Evolution (SGE): Developing a service platform...

report 2014

document

MIP Plasma Decapsulation of Copper-wired Semiconductor Devices for Failure Analysis

Tang, J. (author)

The majority of Integrated Circuit (IC) devices are encapsulated in wire-bonded plastic IC packages. Epoxy molding compound is used as the encapsulation material and gold was used as the bonding wire material. However, the increase of gold material price from 400 USD/ounce in year 2005 to 1400 USD/ounce in year 2013 results in a major cost issue...

doctoral thesis 2014

document

Transistor-Level Statistical Timing Analysis: Solving Random Differential Equations Directly

Tang, Q. (author)

In this Ph.D. thesis, a novel non-MC Random differential Equation based Statistical Timing Analysis (RESTA) method is proposed, which considers both process variations and electrical circuit effects, such as multiple input simultaneous switching and crosstalk effects. To make the approach practical for analysis of large circuits at high accuracy...

doctoral thesis 2013

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Fast Etching of Molding Compound by an Ar/O2/CF4 Plasma and Process Improvements for Semiconductor Package Decapsulation

Tang, J. (author), Gruber, D. (author), Schelen, J.B.J. (author), Funke, H.J. (author), Beenakker, C.I.M. (author)

Decapsulation of a SOT23 semiconductor package with 23 um copper wire bonds is conducted with an especially designed microwave induced plasma system. It is found that a 30%-60% CF4 addition in the O2/CF4 etchant gas results in high molding compound etching rate. Si3N4 overetching which is encountered in plasma decapsulation is solved by an...

journal article 2012

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Iterative equalization for OFDM systems over wideband Multi-Scale Multi-Lag channels

Xu, T. (author), Tang, Z. (author), Remis, R. (author), Leus, G. (author)

OFDM suffers from inter-carrier interference (ICI) when the channel is time varying. This article seeks to quantify the amount of interference resulting from wideband OFDM channels, which are assumed to follow the multi-scale multi-lag (MSML) model. The MSML channel model results in full channel matrices both in the frequency and time domains....

journal article 2012

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Plasma Etching for Failure Analysis of Integrated Circuit Packages

Tang, J. (author), Schelen, J.B.J. (author), Beenakker, C.I.M. (author)

Plastic integrated circuit packages with copper wire bonds are decapsulated by a Microwave Induced Plasma system. Improvements on microwave coupling of the system are achieved by frequency tuning and antenna modification. Plasmas with a mixture of O2 and CF4 showed a high etching rate around 2 mm3/min. The role of O2 and CF4 in etching molding...

journal article 2011

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Identifying time-varying channels with aid of pilots for MIMO-OFDM

Tang, Z. (author), Leus, G.J.T. (author)

In this paper, we consider pilot-aided channel estimation for orthogonal frequency division multiplexing (OFDM) systems with a multiple-input multiple-output setup. The channel is time varying due to Doppler effects and can be approximated by an oversampled complex exponential basis expansion model. We use a best linear unbiased estimator (BLUE)...

journal article 2011

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Are Friends Overrated?: A Study for the Social Aggregator Digg.com

Doerr, C. (author), Tang, S. (author), Blenn, N. (author), Van Mieghem, P. (author)

The key feature of online social networks is the ability of users to become active, make friends and interact with those around them. Such interaction is typically perceived as critical to these platforms; therefore, a significant share of research has investigated the characteristics of social links, friendship relations, community structure,...

conference paper 2011

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Information Propagation in Peer-to-Peer Networking: Modeling and Empirical Studies

Tang, S. (author)

Although being a young technology, peer-to-peer (P2P) networking has spurred dramatic evolution on the Internet over the recent twenty years. Unlike traditional server-client mode, P2P networking applications are user-centric. Users (peers) generate their own content and share it with others across the Internet. Be it a P2P file-sharing network,...

doctoral thesis 2010

document

Influence of assortativity and degree-preserving rewiring on the spectra of networks

Van Mieghem, P. (author), Wang, H. (author), Ge, X. (author), Tang, S. (author), Kuipers, F.A. (author)

Newman’s measure for (dis)assortativity, the linear degree correlation coefficient ?D, is reformulated in terms of the total number Nk of walks in the graph with k hops. This reformulation allows us to derive a new formula from which a degree-preserving rewiring algorithm is deduced, that, in each rewiring step, either increases or decreases ?D...

journal article 2010

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On the convergence of GMRES with invariant-subspace deflation

Yeung, M.C. (author), Tang, J.M. (author), Vuik, C. (author)

We consider the solution of large and sparse linear systems of equations by GMRES. Due to the appearance of unfavorable eigenvalues in the spectrum of the coefficient matrix, the convergence of GMRES may hamper. To overcome this, a deflated variant of GMRES can be used, which treats those unfavorable eigenvalues effectively. In the literature,...

report 2010

document

A Comparison of Two-Level Preconditioners Based on Multigrid and Deflation

Tang, J.M. (author), MacLachlan, S.P. (author), Nabben, R. (author), Vuik, C. (author)

It is well known that two-level and multilevel preconditioned conjugate gradient (PCG) methods provide efficient techniques for solving large and sparse linear systems whose coefficient matrices are symmetric and positive definite. A two-level PCG method combines a traditional (one-level) preconditioner, such as incomplete Cholesky, with a...

journal article 2010

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Topology dynamics in a P2PTV network

Tang, S. (author), Lu, Y. (author), Martín Hernández, J. (author), Kuipers, F.A. (author), Van Mieghem, P. (author)

In recent years, a number of commercial peer-to-peer TV (P2PTV) applications have been launched. Yet, their mechanisms and characteristics are unknown. In this paper, we study SopCast, a typical proprietary P2PTV system. Treating SopCast as a black box, we perform a set of experiments that are suitable to analyze SopCast in depth. We attempt to...

conference paper 2009

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Comparison of Two-Level Preconditioners Derived from Deflation, Domain Decomposition and Multigrid Methods

Tang, J.M. (author), Nabben, R. (author), Vuik, C. (author), Erlangga, Y.A. (author)

For various applications, it is well-known that a multi-level, in particular two-level, preconditioned CG (PCG) method is an efficient method for solving large and sparse linear systems with a coefficient matrix that is symmetric positive definite. The corresponding two-level preconditioner combines traditional and projection-type...

journal article 2009

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Two-level preconditioned conjugate gradient methods with applications to bubbly flow problems

Tang, J.M. (author)

The Preconditioned Conjugate Gradient (PCG) method is one of the most popular iterative methods for solving large linear systems with a symmetric and positive semi-definite coefficient matrix. However, if the preconditioned coefficient matrix is ill-conditioned, the convergence of the PCG method typically deteriorates. Instead, a two-level PCG...

doctoral thesis 2008

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The Effect of Peer Selection with Hopcount or Delay Constraint on Peer-to-Peer Networking

Tang, S. (author), Wang, H. (author), Van Mieghem, P. (author)

conference paper 2008

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A Novel Receiver Architecture for Single-Carrier Transmission over Time-Varying Channels

Tang, Z. (author), Leus, G. (author)

In this paper, we present a single-carrier transceiver for rapidly time-varying channels, where the equalization step is implemented in the frequency domain. When the channel abides with both fast fading and severe inter-block interference, our equalizer relies on a band approximation of the frequencydomain channel matrix to maintain low...

journal article 2008

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Peer Selection with Hopcount and Delay Constraint

Tang, S. (author), Wang, H. (author), Van Mieghem, P. (author)

We revisit the peer selection problem of finding the most nearby peer from an initiating peer. The metrics to assess the closeness between peers are hopcount and delay, respectively. Based on a dense graph model with i.i.d regular link weight, we calculate the probability density function to reach a peer with minimum hopcount and asymptotically...

report 2008

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Fast and robust solvers for pressure correction in bubbly flow problems

MacLachlan, S.P. (author), Tang, J.M. (author), Vuik, C. (author)

report 2008

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Theoretical comparison of two-level preconditioners based on multigrid and deflation

Tang, J.M. (author), MacLachlan, S.P. (author), Nabben, R. (author), Vuik, C. (author)

report 2008