61926198
Integrated Placement and Skew Optimization for Rotary Clocking
The clock distribution network is a key component on any synchronous VLSI design. As technology moves into the nanometer era, innovative clocking techniques are required to solve the power dissipation and variability issues. Rotary clocking is a novel technique which employs unterminated rings formed by differential transmission lines to save power and reduce skew variability. Despite its appealing advantages, rotary clocking requires latch locations to match pre-designed clock skew on rotary clock rings. This requirement is a difficult chicken-and-egg problem which prevents its wide application. In this work, we proposed an integrated placement and skew scheduling methodology to break this hurdle, making rotary clocking compatible with practical design flows. A network flow based latch assignment algorithm and a cost-driven skew optimization algorithm are developed. Experiments show that our method can generate chip placements which satisfy the unique requirements of rotary clocks, without sacrificing design quality. By enabling concurrent clock network and placement design, our method can also be applied in other clocking methodologies as well
28075982
Clock buffer polarity assignment for power noise reduction
11408697
Path-Based Buffer Insertion
Along with the progress of very-large-scale-integration technology, buffer insertion plays an increasingly critical role on affecting circuit design and performance. Traditional buffer insertion algorithms are mostly net based and therefore often result in suboptimal delay or unnecessary buffer expense due to the lack of global view. In this paper, we propose a novel path-based-buffer-insertion (PBBI) scheme which can overcome the weakness of the net-based approaches. We also discuss some potential difficulties of the PBBI approach and propose solutions to them. A fast estimation on buffered delay is employed to improve the solution quality. Gate sizing is also considered at the same time. Experimental results show that our method can efficiently reduce buffer/gate cost significantly (by 71% on average) when compared to traditional net-based approaches. To the best of our knowledge, this is the first work on path based buffer insertion and simultaneous gate sizing.
1271597
An improved AMG-based method for fast power grid analysis
The continuing VLSI technology scaling leads to increasingly significant power supply fluctuations, which needs to be modeled accurately in circuit design and verification. Meanwhile, the huge size of power grid requires its analysis to be fast and highly scalable. Algebraic multigrid (AMG) has been recognized as a promising approach for fast power grid analysis. We propose several techniques to improve AMG-based power grid analysis: (1) dynamic reduction threshold; (2) weighted interpolation; and (3) a new error smoothing scheme. Experimental results on power grid with up to 1.6 million nodes show that these techniques can improve accuracy by over 10 times compared to a reported industrial method while retaining the same fast speed
10406726
Associative Skew Clock Routing for Difficult Instances
In clock network synthesis, sometimes skew constraints are required only within certain groups of clock sinks and do not exist between different groups. This is the so-called associative skew clock routing problem. Although the number of constraints is reduced, the problem becomes more difficult to solve due to the enlarged solution space. The perhaps only previous work used a very primitive delay model and cannot handle difficult instances in which sink groups are intermingled. We reuse existing techniques to solve this problem, including the difficult instances, based on a more accurate and popular delay model. Experimental results show that our algorithm can reduce the total clock routing wirelength by 12% on average compared to greedy-DME which is one of the best zero skew routing algorithms
7189153
Antenna avoidance in layer assignment
The sustained progress of very-large-scale-integration (VLSI) technology has dramatically increased the likelihood of the antenna problem in the manufacturing process and calls for corresponding considerations in the routing stage. In this paper, the authors propose a technique that can handle the antenna problem during the layer-assignment (LA) stage, which is an important step between global routing and detailed routing. The antenna-avoidance problem is modeled as a tree-partitioning problem with a linear-time-optimal-algorithm solution. This algorithm is customized to guide antenna avoidance in the LA stage. A linear-time optimal jumper-insertion algorithm is also derived. Experimental results on benchmark circuits show that the proposed techniques can lead to an average of 76% antenna-violation reduction and 99% via-violation reduction.
17924285
StoryML: Enabling Distributed Interfaces for Interactive Media
This paper introduces an adaptive architecture for presenting interactive timed media onto distributed networked devices. The interactive presentation is documented in StoryML, an XMLbased language, and presented to multiple interface devices organized in an agent-based architecture.
38537514
A Biometric Encryption Approach Incorporating Fingerprint Indexing in Key Generation
This paper presents a new biometric encryption protocol in which encryption key is incorporated with fingerprint indexing. Based on the extended chaotic Baker map, the pixel permutation and gray level value substitution are performed to shuffle pixel positions in the original fingerprint images. The encryption key of the pixel permutation is generated by the combination of the random pixel distribution of a fingerprint imprint as well as features used for the fingerprint indexing. In addition to the advantage enjoyed by biometric keys over traditional password/PINs, the proposed biometric encryption approach is very efficient in identity identification within a large database due to the pre-filtering feature of the fingerprint indexing incorporated in the keys. This approach is applicable to the centralized matching scenario where fingerprints need to be encrypted before transmitted. Simulation results have validated the proposed schemes.
11197335
Traffic grooming, routing, and wavelength assignment in optical WDM mesh networks
In this paper, we consider the traffic grooming, routing, and wavelength assignment (GRWA) problem for optical mesh networks. In most previous studies on optical mesh networks, traffic demands are usually assumed to be wavelength demands, in which case no traffic grooming is needed. In practice, optical networks are typically required to carry a large number of lower rate (sub-wavelength) traffic demands. Hence, the issue of traffic grooming becomes very important since it can significantly impact the overall network cost. In our study, we consider traffic grooming in combination with traffic routing and wavelength assignment. Our objective is to minimize the total number of transponders required in the network. We first formulate the GRWA problem as an integer linear programming (ILP) problem. Unfortunately, for large networks it is computationally infeasible to solve the ILP problem. Therefore, we propose a decomposition method that divides the GRWA problem into two smaller problems: the traffic grooming and routing problem and the wavelength assignment problem, which can then be solved much more efficiently. In general, the decomposition method only produces an approximate solution for the GRWA problem. However, we also provide some sufficient condition under which the decomposition method gives an optimal solution. Finally, some numerical results are provided to demonstrate the efficiency of our method.
6089015
Virtual machine management for Tele-Lab "IT-security" server
Tele-Lab "IT-security" Server is a new concept for practical security education. The Tele-lab server builds a virtual security laboratory using lightweight virtual machines and features a pure Web user interface. Thus, students can easily exercise security over the Internet. Running such a security laboratory on the Internet is difficult. Its infrastructure is subject to misuse and crash due to the nature of security tasks. The management of virtual machines is a crucial component which enables running the Tele-Lab server on the Internet. It effectively saves resources and improves security and reliability of the virtual laboratory. This paper briefly reviews the architecture of the Tele-Lab "IT-security" server, describes its virtual machine management in detail, and presents some experiential and experimental results.
4069319
Attribute Reduction Based on Granular Computing
Attribute reduction is a very important issue in data mining and machine learning. Granular computing is a new kind of soft computing theory. A novel method for encoding granules using bitmap technique is proposed in this paper. A new attribute reduction method based on granular computing is also developed with this encoding method. It is proved to be efficient.