Trends in low-cost, high-performance substrate technology

The trends in high density interconnection (HDI) multichip module (MCM) techniques that have the potential to reduce interconnection cost and production time are described. The implementation in laminated dielectric (MCM-L) technology of a workstation processor core illustrates current substrate technology capabilities. The design, routing, layout and thermal management of the processor core are described. Thin-film deposited dielectric (MCM-D) technology is discussed as a cost-effective method for future interconnection applications     

The virtual reality modeling language explained

VRML stands for Virtual Reality Modeling Language. Technically, VRML is neither virtual reality nor a modeling language. Virtual reality generally implies an immersive 3D experience, which typically requires a head mounted display (HMD) and 3D input devices, such as digital gloves. VRML neither requires nor imposes immersion. Furthermore, a true modeling language would contain richer geometric modeling primitives and mechanisms. VRML provides a bare minimum of geometric modeling features but contains numerous features unavailable in a modeling language. If VRML is not virtual reality or a modeling language, what is it? This question has several answers. At its core, VRML serves as a 3D interchange format. It defines most of the commonly used semantics found in today's 3D applications such as hierarchical transformations, light sources, viewpoints, geometry, animation, fog, material properties, and texture mapping. Here's a second answer to: what is VRML? It's a 3D analog to HTML. This means that VRML serves as a simple, multiplatform language for publishing 3D Web pages. The fact that some information, including games, engineering models, scientific visualizations, educational experiences, and architecture, can best be experienced in 3D has motivated this language. Typically, these types of projects require intensive interaction, animation, and user participation and exploration beyond what a page, text, or image based format can handle. Another answer is that VRML provides the technology to integrate 3D, 2D, text, and multimedia into a coherent model     

Seeking the truth about ad hoc join costs

In this paper, we re-examine the results of prior work on methods for computing ad hoc joins. We develop a detailed cost model for predicting join algorithm performance, and we use the model to develop cost formulas for the major ad hoc join methods found in the relational database literature. We show that various pieces of “common wisdom” about join algorithm performance fail to hold up when analyzed carefully, and we use our detailed cost model to derive op timal buffer allocation schemes for each of the join methods examined here. We show that optimizing their buffer allocations can lead to large performance improvements, e.g., as much as a 400% improvement in some cases. We also validate our cost model's predictions by measuring an actual implementation of each join algorithm considered. The results of this work should be directly useful to implementors of relational query optimizers and query processing systems. Edited by M. Adiba. Received May 1993 / Accepted April 1996     

Effect of immunosuppression and splenectomy in transplantation sarcomas in mice

After spontaneous regression of transplanted tumours, marked reduction in number of tumours was found when challenged with isogenic tumour cells. The ALS abrogates this effect. Tumour removal by surgical excision of limb and subsequent time scheduled challenge by tumour cells maximally suppress on the 10th day and continues up to the 42nd day the tumorogenic effect. Splenectomy has no effect if done before a day or 3 days after challenge but marked decrease in tumour development was seen when challenged on the 8th day after splenectomy. Amputation and splenectomy together potentiates tumour formation. Only in tumour extrication, does resistance develop up to the 42nd day from surgery. Challenging at a different site in mice with tumours, resulted in prolongation of the intervals of tumour formation. Challenge after surgical removal of tumour after a time lapse, results in marked reduction in number and size of tumours. Surgical tumour extrication after splenectomy and subsequent challenge on 11th day inhibited tumour formation. Whereas splenectomized tumour bearing mice when challenged at a heterosite did not develop resistance.