Pathologic fracture is a significant risk for patients afflicted with metastatic or benign skeletal tumors. The quandary for physicians who treat these patients is that after making the diagnosis they must try to predict the load bearing capacity of the involved bone and the fracture risk from images seen in radiological examinations. Since bone fails at a relatively constant strain independent of density we demonstrate that using a mechanics of materials approach that the cross-sectional structural properties of the bone most affected by the lytic defect governs the load bearing capacity of the entire bone.Homogeneous cylindrical cores of trabecular bone were harvested from the vertebral bodies of whale spines, and prepared with circular or slotted through-hole defects of varying sizes to simulate lytic skeletal tumors. Each specimen was imaged using quantitative computed tomography (CT), dual energy X-ray absorptiometry (DXA), and magnetic resonance imaging (MRI) to obtain data for calculating cross-sectional structural properties: axial, flexural, and torsional rigidity. The specimens were then divided into groups uniformly distributed with respect to defect sizes and shapes, and subjected to uniaxial tension, four-point bending or torsion until failure.A strong positive relationship was found between measured tensile yield loads, bending, and torsional yield moments vs. axial, flexural and torsional structural rigidities respectively, calculated from QCT, DXA, and MRI data [QCT: tension r' = 0.951, bending r' = 0.909, torsion 9 = 0.914 ( p < 0.001); DXA: tension t2 = 0.926, bending r2 = 0.841, torsion rZ = 0.916 (p < 0.001); MRI: tension Y' = 0.916; bending r' = 0.856, torsion r2 = 0.852 ( p < 0.00l)l.For cylindrical cores of trabecular bone with simulated lytic defects, the load bearing capacity of the entire core was directly proportional to the axial, bending, or torsional rigidity at the weakest cross-section through the core containing the defect. Therefore structural rigidity analysis of cross-sectional geometric data measured non-invasively by QCT, DXA, and MRI of bones containing lytic defects may be used to predict the load bearing capacity of the involved bone and the relative fracture risk in vivo.

Traditionally, Internet applications have been identified by using predefined well-known ports with questionable accuracy. An alternative approach, applicationlayer signature mapping, involves the exhaustive search of reliable signatures but with more promising accuracy. With a prior protocol knowledge, the signature generation can guarantee a high accuracy. As more applications use proprietary protocols, it becomes increasingly difficult to obtain an accurate signature while avoiding time-consuming and manual signature generation process. This paper proposes an automated approach for generating application-level signature, the LASER algorithm, that does not need to be preceded by an analysis of application protocols. We show that our approach is as accurate and efficient as the approach that uses preceding application protocol analysis.

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This paper presents the design of a next generation network traffic monitoring and analysis system, called NG-MON (Next Generation MONitoring), for high-speed networks such as 10 Gbps and above. Packet capturing and analysis on such high-speed networks is very difficult using traditional approaches. Using distributed, pipelining and parallel processing techniques, we have designed a flexible and scalable monitoring and analysis system, which can run on off-the-shelf, cost-effective computers. The monitoring and analysis task in NG-MON is divided into five phases; packet capture, flow generation, flow store, traffic analysis, and presentation. Each phase can be executed on separate computer systems and cooperates with adjacent phases using pipeline processing. Each phase can be composed of a cluster of computers wherever the system load of the phase is higher than the performance of a single computer system. We have defined efficient communication methods and message formats between phases. Numerical analysis results of our design for 10 Gbps networks are also provided. 1 The authors would like to thank the Ministry of Education of Korea for its financial support toward the Electrical and Computer Engineering Division at POSTECH through its BK21 program.