Damage detection of truss structure based on the variation in axial stress and strain energy predicted from incomplete measurements

This study derives the static equilibrium equation of a damaged system on the basis of stiffness change due to damage as well as the constraint forces at measurements required for obtaining the measured data. Based on the derived equations, this work provides an analytical method to detect damage from the stress and strain energy variations between intact and damaged truss structures. The applicability of the proposed method is evaluated in detecting multiple damages of low rate in the truss structure from measured data contaminated by external noise. It is demonstrated that it is possible to properly detect damage in an isolated substructure by partitioning the damage-expected substructure from an entire structure and using the displacements measured at the boundary of the partitioned subsystem. The partitioning method has the benefits in reducing the computational time and measured data as well as improving the effectiveness of the damage detection process

Entropy bound of local quantum field theory with generalized uncertainty principle

We study the entropy bound for local quantum field theory (LQFT) with generalized uncertainty principle. The generalized uncertainty principle provides naturally a UV cutoff to the LQFT as gravity effects. Imposing the non-gravitational collapse condition as the UV-IR relation, we find that the maximal entropy of a bosonic field is limited by the entropy bound $A^{3/4}$ rather than $A$ with $A$ the boundary area.Comment: 11 pages, 1figure, version to appear in PL

Symplectic Embedding of a Massive Vector-Tensor Theory with Topological Coupling

In the symplectic Lagrangian framework we newly embed an irreducible massive vector-tensor theory into a gauge invariant system, which has become reducible, by extending the configuration space to include an additional pair of scalar and vector fields, which give the desired Wess-Zumino action. A comparision with the BFT Hamiltonian embedding approach is also done.Comment: LaTeX file, 23 page

THE EFFECTS OF WEARING ROLLER SHOES ON MUSCLE ACTIVITY IN THE LOWER EXTREMITY DURING WALKING

Roller shoes have become increasingly popular among children and its features of retractable wheels which allow the user to walk or roll without changing the footwear. Maintaining balance during forward walking with roller shoes is not an easy task. To prevent falling backward, the user needs to lock the knees and tighten the ankles and thighs while the upper body is slightly leaning forward. Constant walking with roller shoes forces the user to walk in a manner much different from normal gait. Prolonged exposure to un-natural stresses on human body forces our body to evolve by strengthening those incorrect and temporary functions (Clement et al., 1981). For children, the chronic stress may lead to serious injuries in the lower extremity later in life. If any potential of injury exists in a movement it is critical to examine the associated muscle activity that may lead to injury. To the best of our knowledge, the effects of wearing roller shoes on muscle activity in the lower extremity have rarely been studied, especially in the youth population. Thus, the purpose of this study was to compare muscle activity in the lower extremity during walking wearing jogging and roller shoes

Prognostic Value of Postoperative CEA Clearance in Rectal Cancer Patients with High Preoperative CEA Levels

PURPOSE: We determined the prognostic value of carcinoembryonic antigen (CEA) clearance after tumor resection with serial evaluation of postoperative CEA levels in rectal cancer. METHODS: Between 1994 and 2004, we retrospectively reviewed 122 patients with rectal cancer whose serum CEA levels were measured on the preoperative day and postoperative days 7 and 30. Patients with preoperative CEA levels <5.0 ng/ml were excluded. An exponential trend line was drawn using the three CEA values. Patients were categorized into three groups based on R(2) values calculated through trend line, which indicates the correlation coefficient between exponential graph and measured CEA values: exponential decrease group (group 1: 0.9 < R(2) < or = 1.0), nearly exponential decrease group (group 2: 0.5 < R(2) < or = 0.9), and randomized clearance group (group 3: 0.5 < or = R(2)). We then analyzed the CEA clearance pattern as a prognostic indicator. RESULTS: With a median follow-up of 57 months, the 5-year overall survival was 62.3% vs. 48.1% vs. 25% and the 5-year disease-free survival was 58.6% vs. 52.7% vs. 25% among groups 1, 2, and 3 (P = 0.014, P = 0.027, respectively) in patients with stage III rectal cancer. For those with stage II rectal cancer, the 5-year overall survival rate of group 1 was significantly better than groups 2 and 3 (88.8% vs. 74.1%, respectively, P = 0.021). CONCLUSIONS: the postoperative pattern of CEA clearance is a useful prognostic determinant in patients with rectal cancer. Patients with a randomized pattern of CEA clearance after tumor resection should be regarded as having the possibility of a persistent CEA source and may require consideration of intensive follow-up or adjuvant therapy.ope