Opportunity Initiated Systems Design: A Case Study

The field of Instructional Systems Design (ISD) provides models from which instructional changes can be designed and implemented. In ISD programs, students develop skills in the application of this process and apply these skills in a variety of settings. Although our models also provide a framework from which program change can proceed, few examples exist of the application of ISD to the design of an educational system (Squire, 1999). In this paper we describe the application of Opportunity Initiated Systems Design, apractitioner-based ISD model, in light of our own formative evaluation and program revision of the Instructional Design and Technology program at the University of Iowa. In this case study, we found that the communication of shared definitions was critical and that the probabilistic nature of the model was not a limitation but rather a prompt for further opportunities.     

Scaling laws of marine predator search behaviour

Many free-ranging predators have to make foraging decisions with little, if any, knowledge of present resource distribution and availability. The optimal search strategy they should use to maximize encounter rates with prey in heterogeneous natural environments remains a largely unresolved issue in ecology. Lévy walks are specialized random walks giving rise to fractal movement trajectories that may represent an optimal solution for searching complex landscapes. However, the adaptive significance of this putative strategy in response to natural prey distributions remains untested. Here we analyse over a million movement displacements recorded from animal-attached electronic tags to show that diverse marine predators-sharks, bony fishes, sea turtles and penguins-exhibit Lévy-walk-like behaviour close to a theoretical optimum. Prey density distributions also display Lévy-like fractal patterns, suggesting response movements by predators to prey distributions. Simulations show that predators have higher encounter rates when adopting Lévy-type foraging in natural-like prey fields compared with purely random landscapes. This is consistent with the hypothesis that observed search patterns are adapted to observed statistical patterns of the landscape. This may explain why Lévy-like behaviour seems to be widespread among diverse organisms, from microbes to humans, as a 'rule' that evolved in response to patchy resource distributions.     

Implementation Study of Dynamic Load Balancing Algorithm of Parallel Tree Computation on Clusters of Heterogeneous Workstation

Introduction Inthe1980sresearchersbelievedthatthebestwayto improvecomputerperformancewasbycreatingfasterand momefficientprocessors.Thisideawaschallengedby parallelprocessingwhichinessencemeanslinkingtogether twoormorecomputerstosolvejointlyacomputational problem.Inearly1990sthetrendwastomoveawayfrom expensiveandspecializedproprietarysupercomputers towardsnetworkofworkstations,producinganew computingplatformcalledCOW.[1]Theemergenceof COWhasbeenfosterednotonlybyrecentadvancesin computerhardw…     

Abnormal TNF activity in Timp3-/- mice leads to chronic hepatic inflammation and failure of liver regeneration

Tumor-necrosis factor (TNF), a pleiotropic cytokine, triggers physiological and pathological responses in several organs. Here we show that deletion of the mouse gene Timp3 resulted in an increase in TNF-alpha converting enzyme activity, constitutive release of TNF and activation of TNF signaling in the liver. The increase in TNF in Timp3(-/-) mice culminated in hepatic lymphocyte infiltration and necrosis, features that are also seen in chronic active hepatitis in humans. This pathology was prevented when deletion of Timp3 was combined with Tnfrsf1a deficiency. In a liver regeneration model that requires TNF signaling, Timp3(-/-) mice succumbed to liver failure. Hepatocytes from Timp3(-/-) mice completed the cell cycle but then underwent cell death owing to sustained activation of TNF. This hepatocyte cell death was completely rescued by a neutralizing antibody to TNF. Dysregulation of TNF occurred specifically in Timp3(-/-), and not Timp1(-/-) mice. These data indicate that TIMP3 is a crucial innate negative regulator of TNF in both tissue homeostasis and tissue response to injury.     

Relative Degree Structural Hole Centrality,CRD−SH: A New Centrality Measure in Complex Networks

In order to assess influential nodes in complex networks, the authors propose a novel ranking method based on structural hole in combination with the degree ratio of a node and its neighbors. The proposed method is a response to the limitations of other proposed measures in this field. The structural hole gives a comprehensive attention of the information about the node topology in relation to its neighbors, whereas the degree ratio of nodes reflects its significance against the neighbors.Combination of the two aforementioned measures summarized in the structural hole leverage matrix demonstrates the importance of a node according to its position in the network structure. So a more accurate method for ranking influential nodes is established. The simulation results over different-scale networks(small networks with less than 30 nodes, medium networks with less than 150 nodes and large networks with more than 1000 nodes) suggest that the proposed method can rank important nodes more effectively and precisely in complex networks specifically in larger ones.