The component-based software engineering has been gaining attention in consumer electronics (CE) industry. New component models for CE software are emerging, but unfortunately there is no common standard established yet. Each of the proposed models focuses on satisfying some subset of requirements from CE software and there is no unified model that can handle all different requirements ofCE software. We propose a component model for component- based CE software development in the context of software product lines. The component model focuses on handling build-time structures of the software and attempts to provide a unified model that can support both componentization of legacy code and composition of new CE software in an efficient way. We also describe our experiences in prototyping a tool and applying it to one of our initial CE product line implementations.

Many object-oriented database systems manage object buffers to provide fast access to objects. Traditional buffer replacement algorithms based on fixed-length pages simply assume that the cost incurred by operating a buffer is proportional to the number of buffer faults. However, this assumption no longer holds in an object buffer where objects are of variable-lengths and the cost of replacing an object varies for each object. We propose a cost-based replacement algorithm for object buffers. The proposed algorithm replaces the objects that have minimum costs per unit time and unit space. The cost model extends the previous page-based one to include the replacement costs and the sizes of objects. The performance tests show that the proposed algorithm is almost always superior to the LRU-2 algorithm and, when significant replacement cost is involved, is more than twice as fast.

Ray tracing requires many ray-object intersection tests. A way of reducing the number of ray-object intersection tests is to subdivide the space occupied by objects into many nonoverlapping subregions, called voxels, and to construct an octree for the subdivided space. We propose the Octree-R, an octree-variant data structure for efficient ray tracing. The algorithm for constructing the Octree-R first estimates the number of ray-object intersection tests. Then, it partitions the space along the plane that minimizes the estimated number of ray-object intersection tests. We present the results of experiments for verifying the effectiveness of the Octree-R. In the experiment, the Octree-R provides a 4% to 47% performance gain over the conventional octree. The result shows the more skewed the object distribution (as is typical for real data), the more performance gain the Octree-R achieves.

Orthogonal persistence, a property that any object can be made to persist independent of its type, is an important requirement of a persistent language. We present a new technique called forced inheritance for providing the orthogonal persistence to C++. In this technique, properties that make objects persist are attached as a header to an object or a value of any type that is desired to persist. Attaching the header gives the effect of inheriting these properties from a virtual persistent root class regardless of its type. This technique provides orthogonal persistence since attaching the header to an object can be done for any object. It also provides portability since it does not extend the language. The new, approach not only has advantages over existing ones, but also can be efficiently implemented.>