62556261
An enhanced appearance model for ultrasound image segmentation
Active appearance model (AAM) had been popular on object segmentation for medical images. However, its performance is not good on ultrasound (US) images. In this paper, we propose an enhanced appearance model which represents the texture by edge structure and reduces the view-dependent feature of US images by a novel data normalization process. In our experiments on general US data, the proposed model shows considerable improvements compared to the original one.
16998450
Consistent multi-modal non-rigid registration based on a variational approach
In this paper, a novel variational approach for multi-modal image registration based on consistent non-rigid transforms is proposed. The forward and backward transforms are computed in a variational framework simultaneously. A consistency energy is added into the variational registration framework and an iterative method assures that the forward and backward transforms are close approximate inverses of each other. This new scheme can provide more constraints on the forward and backward transforms and make them smoother. This reduces the chance of being stuck into a local minimum. We can incorporate the consistent transforms together with several kinds of information based similarity metrics such as mutual information and correlation ratio into the registration framework. An implicit finite difference scheme is used to solve the Euler-Lagrange equation numerically. Our proposed method is evaluated by using simulated multi-modal magnetic resonance images (MRI) and real medical images. The results of our proposed consistent registration and those using only forward or backward registration are compared. Improvements at the edge area can be easily seen from the registration results.
22330856
Shape Alignment by Learning a Landmark-PDM Coupled Model
This paper revisits the model-based approaches for groupwise shape alignment. The key contribution is modeling the landmarks instead of considering them as nodes sliding along the shape contour. The shape group is thus modeled by a landmark-PDM coupled model instead of a constrained point distribution model (PDM). This coupled model is estimated by a stable four-stage estimation algorithm. There are two significant achievements. First, shapes are aligned in a fully unsupervised manner - both the number and location of landmarks are automatically decided. Second, extremely noisy and largely deformed shapes can be robustly aligned. These are demonstrated using both synthesized and real data
11558088
A basic stochastic network calculus
A basic calculus is presented for stochastic service guarantee analysis in communication networks. Central to the calculus are two definitions, maximum-(virtual)-backlog-centric (m. b. c) stochastic arrival curve and stochastic service curve, which respectively generalize arrival curve and service curve in the deterministic network calculus framework. With m. b. c stochastic arrival curve and stochastic service curve, various basic results are derived under the (min, +)algebra for the general case analysis, which are crucial to the development of stochastic network calculus. These results include (i)superposition of flows, (ii)concatenation of servers, (iii) output characterization, (iv)per-flow service under aggregation, and (v)stochastic backlog and delay guarantees. In addition, to perform independent case analysis, stochastic strict server is defined, which uses an ideal service process and an impairment process to characterize a server. The concept of stochastic strict server not only allows us to improve the basic results (i)-(v)under the independent case, but also provides a convenient way to find the stochastic service curve of a serve. Moreover, an approach is introduced to find the m.b.c stochastic arrival curve of a flow and the stochastic service curve of a server.
6410925
Effects of Low-Quality Computation Time Estimates in Policed Schedulers
Researchers conducting computer simulations can often provide estimates of computation time for a given type of simulation, which may be used by the compute cluster to aid in resource allocation and scheduling. However, the low quality of these estimates can cause deadline misses and unpredictable behavior. This problem is exacerbated on complex compute resources, clusters, and grids. Past-deadline jobs may be killed to provide resources for others, but the effect on the throughput of whole batches not fully understood. In this paper, we examine models for simple job schedulers and examine the quality of the deadline guarantee given. Simulation results based on actual runtimes are provided and discussed
43859012
Dynamic parallel query processing for distributed objects
An effective exploitation of distributed computing environments to improve the performance of large advanced database applications requires parallel query processing techniques. This is because parallel query execution can be achieved by operations of pipelining and data partitioning, as well as independent subqueries. In order to develop efficient parallel query services in distributed environments, we present a query optimization, a dynamic parallel query scheduling algorithm, and an implementation mechanism for querying distributed objects. Our proposal has four important features. First, the query schedule dynamically schedules independent subqueries in parallel. Second, distributed processors are allowed to execute independent subqueries in random. Third, it doesn't limit the number of processors to deal with parallel query processing in a network based computing environment. Fourth, it provides simple operations to synchronize parallel query programs. We give the query optimization for parallel processing, show an algorithm of dynamic parallel query scheduling, describe an implementation method for the parallel query processing in a network-based distributed computing environment, and present the design of communication and synchronization for the parallel query processing.
41802198
Dynamic Service Matchmaking in Intelligent Web
Intelligent Web functions essentially as an enormously autonomic entity, and it automatically regulates the functions and cooperation of related Web sites and available application services. Agent is the core component of the Intelligent Web. Intelligent Web not only can present the static information, but also can present dynamic services. In this paper, we study the problems of service management in Intelligent Web and analyze the insufficiencies of the service description language CDL, SDL and LARKS. Combining the features of the Intelligent Web, Web Services, and Grid Services, we propose an agent service description language SDLSIN which satisfies ten properties of agent service description. Based on SDLSIN, we mainly study the service matchmaking problem of Intelligent Web, and propose three kinds of service matchmaking algorithms which are adapted to open and dynamic Intelligent Web. At last, the development of SDLSIN and three kinds of service matchmaking algorithms in Multi-AGent Environment MAGE which we developed is introduced.