An efficient implementation of SELF, a dynamically-typed object-oriented language based on prototypes

We have developed and implemented techniques that double the performance of dynamically-typed object-oriented languages. Our SELF implementation runs twice as fast as the fastest Smalltalk implementation, despite SELF's lack of classes and explicit variables.To compensate for the absence of classes, our system uses implementation-levelmaps to transparently group objects cloned from the same prototype, providing data type information and eliminating the apparent space overhead for prototype-based systems. To compensate for dynamic typing, user-defined control structures, and the lack of explicit variables, our system dynamically compilesmultiple versions of a source method, eachcustomized according to its receiver's map. Within each version the type of the receiver is fixed, and thus the compiler can statically bind andinline all messages sent toself.Message splitting andtype prediction extract and preserve even more static type information, allowing the compiler to inline many other messages. Inlining dramatically improves performance and eliminates the need to hard-wire low-level methods such as+, ==, andifTrue:.Despite inlining and other optimizations, our system still supports interactive programming environments. The system traverses internal dependency lists to invalidate all compiled methods affected by a programming change. The debugger reconstructs inlined stack frames from compiler-generated debugging information, making inlining invisible to the SELF programmer.This work has been generously supported by National Science Foundation Presidential Young Investigator Grant #CCR-8657631, and by IBM, Texas Instruments, NCR, Tandem Computers, Apple Computer, and Sun Microsystems.This paper was originally published inOOPSLA '89 Conference Proceedings (SIGPLAN Notices, 25, 10 (1989) 49–70).     

Bandwidth and region division for broadband multi-cell networks

A cell planning technique termed BRD (bandwidth and region division) is presented for overcoming interference, maintaining QoS (quality of service) and improving channel capacity over OFDM (orthogonal frequency division multiplexing)-based broadband cellular networks. Through an optimal combination of sectorization and zero padding, bandwidth and region division is achieved that minimizes the outage probability for forward-link cell planning. In order to verify the effectiveness of the proposed algorithm, a Monte Carlo simulation is performed over multi-cell environments.     

A practical approach for statistical matching of output queueing

We study a practical approach to match the performance of an output-queued switch statistically. For this purpose, we propose a novel switching architecture called a multiple input/output-queued (MIOQ) switch that requires no speedup for providing sufficient switching bandwidth. To operate an MIOQ switch in a practical manner, we also propose a multitoken-based arbiter which schedules the switch at a high operation rate and a virtual first-in first-out queueing scheme which guarantees the departure order of cells belonging to the same traffic flow at output. Additionally, we show that the proposed switch can naturally provide asymmetric bandwidth for inputs and outputs, which may be important in dealing with the links with different bandwidth demands. Finally, we compare the performance of an MIOQ switch with that of an output-queued switch and discuss the design criteria to match the performance of an output-queued switch.     

Data retention characteristics of sub-100 nm NAND flash memory cells

In contrast to the conventional theories, we have revealed that the most distinguished mechanism in the data retention phenomenon after Fowler-Nordheim (FN) stress in sub-100 nm NAND Flash memory cells is the annihilation of interface states. Interface state generation rate increases rapidly as the channel width of NAND flash cell decreases. Comparison of interface states and stress-induced leakage current (SILC) component during retention mode shows that the annihilation of interface states strongly affects data retention characteristics of the programmed cells.     

Catalytic dehydrogenation of ethylbenzene with carbon dioxide: promotional effect of antimony in supported vanadium–antimony oxide catalyst

Alumina-supported vanadium oxide, VO_x/Al₂O₃, and binary vanadium–antimony oxides, VSbO_x/Al₂O₃, have been tested in the ethylbenzene dehydrogenation with carbon dioxide and characterized by S_BET, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction and CO₂ pulse methods. VSbO_x/Al₂O₃ exhibited enhanced catalytic activity and especially on-stream stability compared to VO_x/Al₂O₃ catalyst. Incorporation of antimony into VO_x/Al₂O₃ increased dispersion of active VO_x species, enhanced redox properties of the systems and formed a new mixed vanadium–antimony oxide phase in the most catalytically efficient V_0.43Sb_0.57O_x/Al₂O₃ system.     

89-GHz fT room-temperature silicon MOSFETs

The authors report the implementation of deep-submicrometer Si MOSFETs that at room temperature have a unity-current-gain cutoff frequency (f_T) of 89 GHz, for a drain-to-source bias of 1.5 V, a gate-to-source bias of 1 V, a gate oxide thickness of 40 Å, and a channel length of 0.15 μm. The fabrication procedure is mostly conventional, except for the e-beam defined gates. The speed performance is achieved through an intrinsic transit time of only 1.8 ps across the active device region     

TennisViewer: a browser for competition trees

A tennis novice watching a match for the first time might be surprised that the crowd erupts with cheers when a player wins one point, then barely applauds when he wins the next. The crowd is not necessarily fickle; some points are genuinely more important than others because a tennis match is hierarchically structured. One match consists of several sets. One set consists of several games. One game consists of several points. The match-winning point is the most important one. How can we make that importance visible? Our goal is to let a fan, a player, or a coach examine tennis data visually, extract the interesting parts, and jump from one item to another quickly and easily. The visualization tool should help parse the elements of a match. We developed an interactive system called TennisViewer to visualize the dynamic, tree-structured data representing a tennis match. It provides an interface for users to quickly explore tennis match information. The visualization tool reveals the overall structure of the match as well as the fine details in a single screen. It uses a 2D display of translucent layers, a design that contains elements of Tree-Maps and of the Visual Scheduler system, which was designed to help faculty and students identify mutually available (transparent) time slots when arranging group meetings. TennisViewer provides MagicLens filters to explore specialized views of the information and a time-varying display to animate all or part of a match