Adaptive control based on explicit model of robot manipulator

Adaptive and nonadaptive control algorithms, which make use of a fundamental mathematical property concerning positive definite matrices and Lyapunov stability theory, are proposed for the control of robot manipulators. Using the fact that the matrix dD(q)/dt-2C(q, dq/ dt) is skew symmetric, nonadaptive controllers which have a simplified structure with less computational burden are proposed. Using the dynamic equations for robot manipulators, parameter adaptation rules are developed for updating the controller's partially or totally unknown parameters, generalizing them to model reference adaptive controllers. To further take advantage of the simplified structure of the proposed adaptive controllers, a method for deriving the dynamic model of a robot manipulator which is linear in terms of its parameters is given. This dynamic model is also suitable for the pure identification of the parameters of links and payload of the manipulator     

Compound C Inhibits Renca Renal Epithelial Carcinoma Growth in Syngeneic Mouse Models by Blocking Cell Cycle Progression,Adhesion and Invasion

Compound C (CompC), an inhibitor of AMP-activated protein kinase, reduces the viability of various renal carcinoma cells. The molecular mechanism underlying anti-proliferative effect was investigated by flow cytometry and western blot analysis in Renca cells. Its effect on the growth of Renca xenografts was also examined in a syngeneic BALB/c mouse model. Subsequent results demonstrated that CompC reduced platelet-derived growth factor receptor signaling pathways and increased ERK1/2 activation as well as reactive oxygen species (ROS) production. CompC also increased the level of active Wee1 tyrosine kinase (P-Ser⁶⁴²-Wee1) and the inactive form of Cdk1 (P-Tyr¹⁵-Cdk1) while reducing the level of active histone H3 (P-Ser¹⁰-H3). ROS-dependent ERK1/2 activation and sequential alterations in Wee1, Cdk1, and histone H3 might be responsible for the CompC-induced G2/M cell cycle arrest and cell viability reduction. In addition, CompC reduced the adhesion, migration, and invasion of Renca cells in the in vitro cell systems, and growth of Renca xenografts in the BALB/c mouse model. Taken together, the inhibition of in vivo tumor growth by CompC may be attributed to the blockage of cell cycle progression, adhesion, migration, and invasion of tumor cells. These findings suggest the therapeutic potential of CompC against tumor development and progression.     

Novel specimen for the effective measurement of the fracture strain along with stress triaxiality and Lode parameter

A double notched central hole, i.e., DNC specimen, which contains a center hole with a left side notch and a right side notch accompanying the slope α, is proposed to simultaneously achieve dual values of stress triaxiality and Lode parameter from one specimen in the present study. Analytical and numerical approaches are carried out under decent assumptions to characterize the plane strain behavior of DNC specimen along with the slope α. Quasi-static tensile tests with conventional specimens and DNC specimens revealed plastic strains at fracture for each specimen case in accordance with stress triaxiality and Lode parameter by digital image correlation. It is found that one DNC specimen successfully provides dual values of stress triaxiality and Lode parameter at the same time; therefore, it saves up to 50 % of experimental time and labor of conventional specimens.

     

Extended OLSR and AODV based on multi-criteria decision making method

Telecommunication Systems - Recently, multi-metric routing protocols have been proposed to enhance the performance of the typical single metric routing protocols in mobile ad-hoc networks....     

Understanding the Experiences of Relocatees during Forced Relocation in Chinese Urban Restructuring

Despite the massive forced relocation of residents during urban restructuring in China, there is no systematic overview regarding how residents experience the process and its outcomes. Most studies concerning urban restructuring in China directly equate forced relocation with displacement, which has a negative connotation. This predominantly negative view overlooks the multifaceted effects of forced relocation on relocatees. This paper aims to provide a better understanding of relocatees’ experiences during urban redevelopment in China by establishing a conceptual model in which the time sequence of events and their context are central. It conceptualizes forced relocation as a process with various and changing socio-spatial implications over time, and as a specific type of residential mobility that occurs in the context of urban restructuring. As such, the conceptual model divides the process of forced relocation into a pre-demolition stage, a transitional stage and a post-relocation stage and investigates the social, economic, physical, psychological and behavioural dimensions of the experiences of relocatees as affected by the macro and micro context. The conceptual model is used to structure the analysis of the existing literature about residents’ experiences and to subsequently identify the gaps in the literature that should be addressed in future studies of forced relocation in the Chinese context.     

Powered wheelchairs: are we enabling or disabling?

The sonographic diagnosis of malignant lymphoma in childhood is described. Malignant lymphomas are sonographically relatively uniform: initial enlargement of the lymph nodes and organs involved and disturbance of normal echo texture by mainly hypoechoic lesions can be found. Generally, four sonographic patterns of infiltration are described: diffuse, small nodular, large nodular and bulky type. Secondary, tumor-related or inflammatory complications (e.g. dislocation or compression of vessels, thoracic inlet syndrome, venous thrombosis, ileus, urinary retention, abscess and effusion) can be sonographically evaluated. Response to therapy correlates with normalization of size and echo texture and recovery from tumor-related complications. Differential diagnosis with ultrasound is based on the topographic distribution and echo pattern of infiltration and, with certain restrictions, on the echogenicity of lesions and perfusion feasible with Doppler sonography. The primary diagnosis has to be established histologically.     

Modeling and control of an LDPE autoclave reactor

A two-compartment four-cell model is developed for the adiabetic slim type autoclave reactor for free radical polymerization of low density polyethylene (LDPE). It is possible to determine not only the reactor performance represented by the monomer conversion and the reaction temperature but also the properties of the polymer product characterized by the average molecular weight and the polydispersity. It turns out that the reactor performance predicted is in good agreement with the plant data and the properties of the polymer product are estimated within reasonable ranges of actual values. The steady state multiplicity is found to exist and is examined by constructing the bifurcation diagram. The effects of various operation parameters on the reactor performance and the polymer properties are investigated systematically to show that the temperature distribution plays the central role for the properties of the polymer products. Therefore, it is essential to establish a good control strategy for the temperature in each compartment. The adaptive pole-placement control algorithm is applied to the temperature control of the adiabatic slim type autoclave reactor. The recursive least square method is used for the model identification. To accomplish a satisfactory control, the estimator and controller are initialized during the period of start-up. It is shown that the reactor system can be adaptively controlled by the pole-placement control algorithm, especially when the reactor temperature distribution is changed.     

The effect of steam temperature on the economics of a cogeneration power plant

Using steady-state simulation, we have evaluated the effect of boiler superheat and reheat temperatures on the economics of the utility section of a Bayer Alumina Plant. These economics were compared with those of a steam plant which purchased power. Under this study's nominal economic conditions, producing steam and purchasing electricity was the cheaper option. A sensitivity analysis showed that the cogeneration plant became the better choice when the local cost of electricity rose above 10C/kWh. The plant economics improved monotonically with superheat temperature as did the thermo-dynamic efficiency. However, for reheat, the plant economics did not improve monotonically with temperature even though the thermodynamic eficiency did; thus improvement in the thermodynamic efficiency does not always yield improved economics.