Information Filtering for Ultrasound-based Real-time Registration

This paper presents methods based on Information Filters for solving matching problems with emphasis on real-time, or effectively real-time applications. Both applications discussed in this work deal with ultrasound-based rigid registration in computer-assisted orthopedic surgery. In the first application, the usual workflow of rigid registration is reformulated such that registration algorithms would iterate while the surgeon is acquiring ultrasound images of the anatomy to be operated. Using this effectively real-time approach to registration, the surgeon would then receive feedback in order to better gauge the quality of the final registration outcome. The second application considered in this paper circumvents the need to attach physical markers to bones for anatomical referencing. Experiments using anatomical objects immersed in water are performed in order to evaluate and compare the different methods presented herein, using both 2D as well as real-time 3D ultrasound.

Unanticipated Partial Behavioral Reflection: Adapting Applications at Runtime

Dynamic, unanticipated adaptation of running systems is of interest in a variety of situations, ranging from functional upgrades to on-the-fly debugging or monitoring of critical applications. In this paper we study a particular form of computational reflection, called unanticipated partial behavioral reflection, which is particularly well-suited for unanticipated adaptation of real-world systems. Our proposal combines the dynamicity of unanticipated reflection, i.e. reflection that does not require preparation of the code of any sort, and the selectivity and efficiency of partial behavioral reflection. First, we propose unanticipated partial behavioral reflection which enables the developer to precisely select the required reifications, to flexibly engineer the metalevel and to introduce the meta behavior dynamically. Second, we present a system supporting unanticipated partial behavioral reflection in Squeak Smalltalk, called Geppetto, and illustrate its use with a concrete example of a web application. Benchmarks validate the applicability of our proposal as an extension to the standard reflective abilities of Smalltalk.

Enhancing IEEE 802.11 Energy Efficiency for Continuous Media Applications

This paper proposes the Optimized Power save Algorithm for continuous Media Applications (OPAMA) to improve end-user device energy efficiency. OPAMA enhances the standard legacy Power Save Mode (PSM) of IEEE 802.11 by taking into consideration application specific requirements combined with data aggregation techniques. By establishing a balanced cost/benefit tradeoff between performance and energy consumption, OPAMA is able to improve energy efficiency, while keeping the end-user experience at a desired level. OPAMA was assessed in the OMNeT++ simulator using real traces of variable bitrate video streaming applications. The results showed the capability to enhance energy efficiency, achieving savings up to 44% when compared with the IEEE 802.11 legacy PSM.

A Near-Real-Time Automatic Orbit Determination System for COSMIC and Its Follow-On Satellite Mission: Analysis of Orbit and Clock Errors on Radio Occultation

The COSMIC-2 mission is a follow-on mission of the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) with an upgraded payload for improved radio occultation (RO) applications. The objective of this paper is to develop a near-real-time (NRT) orbit determination system, called NRT National Chiao Tung University (NCTU) system, to support COSMIC-2 in atmospheric applications and verify the orbit product of COSMIC. The system is capable of automatic determinations of the NRT GPS clocks and LEO orbit and clock. To assess the NRT (NCTU) system, we use eight days of COSMIC data (March 24-31, 2011), which contain a total of 331 GPS observation sessions and 12 393 RO observable files. The parallel scheduling for independent GPS and LEO estimations and automatic time matching improves the computational efficiency by 64% compared to the sequential scheduling. Orbit difference analyses suggest a 10-cm accuracy for the COSMIC orbits from the NRT (NCTU) system, and it is consistent as the NRT University Corporation for Atmospheric Research (URCA) system. The mean velocity accuracy from the NRT orbits of COSMIC is 0.168 mm/s, corresponding to an error of about 0.051 μrad in the bending angle. The rms differences in the NRT COSMIC clock and in GPS clocks between the NRT (NCTU) and the postprocessing products are 3.742 and 1.427 ns. The GPS clocks determined from a partial ground GPS network [from NRT (NCTU)] and a full one [from NRT (UCAR)] result in mean rms frequency stabilities of 6.1E-12 and 2.7E-12, respectively, corresponding to range fluctuations of 5.5 and 2.4 cm and bending angle errors of 3.75 and 1.66 μrad .

Food Volume Computation for Self Dietary Assessment Applications

There is great demand for easily-accessible, user-friendly dietary self-management applications. Yet accurate, fully-automatic estimation of nutritional intake using computer vision methods remains an open research problem. One key element of this problem is the volume estimation, which can be computed from 3D models obtained using multi-view geometry. The paper presents a computational system for volume estimation based on the processing of two meal images. A 3D model of the served meal is reconstructed using the acquired images and the volume is computed from the shape. The algorithm was tested on food models (dummy foods) with known volume and on real served food. Volume accuracy was in the order of 90 %, while the total execution time was below 15 seconds per image pair. The proposed system combines simple and computational affordable methods for 3D reconstruction, remained stable throughout the experiments, operates in near real time, and places minimum constraints on users.

An IEEE 802.11 energy efficient mechanism for continuous media applications

The widespread deployment of wireless mobile communications enables an almost permanent usage of portable devices, which imposes high demands on the battery of these devices. Indeed, battery lifetime is becoming one the most critical factors on the end-users satisfaction when using wireless communications. In this work, the optimized power save algorithm for continuous media applications (OPAMA) is proposed, aiming at enhancing the energy efficiency on end-users devices. By combining the application specific requirements with data aggregation techniques, {OPAMA} improves the standard {IEEE} 802.11 legacy Power Save Mode (PSM) performance. The algorithm uses the feedback on the end-user expected quality to establish a proper tradeoff between energy consumption and application performance. {OPAMA} was assessed in the OMNeT++ simulator, using real traces of variable bitrate video streaming applications, and in a real testbed employing a novel methodology intended to perform an accurate evaluation concerning video Quality of Experience (QoE) perceived by the end-users. The results revealed the {OPAMA} capability to enhance energy efficiency without degrading the end-user observed QoE, achieving savings up to 44 when compared with the {IEEE} 802.11 legacy PSM.

Relative indexes of cutaneous blood perfusion measured by real-time laser Doppler imaging (LDI) in healthy volunteers.

We used real-time LDI to study regional variations in microcirculatory perfusion in healthy candidates to establish a new methodology for global perfusion body mapping that is based on intra-individual perfusion index ratios. Our study included 74 (37 female) healthy volunteers aged between 22 and 30 years (mean 24.49). Imaging was performed using a recent microcirculation-imaging camera (EasyLDI) for different body regions of each volunteer. The perfusion values were reported in Arbitrary Perfusion Units (APU). The relative perfusion indexes for each candidate's body region were then obtained by normalization with the perfusion value of the forehead. Basic parameters such as weight, height, and blood pressure were also measured and analyzed. The highest mean perfusion value was reported in the forehead area (259.21APU). Mean perfusion in the measured parts of the body correlated positively with mean forehead value, while there was no significant correlation between forehead blood perfusion values and room temperature, BMI, systolic blood pressure and diastolic blood pressure (p=0.420, 0.623, 0.488, 0.099, respectively). Analysis of the data showed that perfusion indexes were not significantly different between male and female volunteers except for the ventral upper arm area (p=.001). LDI is a non-invasive, fast technique that opens several avenues for clinical applications. The mean perfusion indexes are useful in clinical practice for monitoring patients before and after surgical interventions. Perfusion values can be predicted for different body parts for patients only by taking the forehead perfusion value and using the perfusion index ratios to obtain expected normative perfusion values.

Simulation of SLA-based VM-scaling algorithms for cloud-distributed applications

Cloud Computing has evolved to become an enabler for delivering access to large scale distributed applications running on managed network-connected computing systems. This makes possible hosting Distributed Enterprise Information Systems (dEISs) in cloud environments, while enforcing strict performance and quality of service requirements, defined using Service Level Agreements (SLAs). {SLAs} define the performance boundaries of distributed applications, and are enforced by a cloud management system (CMS) dynamically allocating the available computing resources to the cloud services. We present two novel VM-scaling algorithms focused on dEIS systems, which optimally detect most appropriate scaling conditions using performance-models of distributed applications derived from constant-workload benchmarks, together with SLA-specified performance constraints. We simulate the VM-scaling algorithms in a cloud simulator and compare against trace-based performance models of dEISs. We compare a total of three SLA-based VM-scaling algorithms (one using prediction mechanisms) based on a real-world application scenario involving a large variable number of users. Our results show that it is beneficial to use autoregressive predictive SLA-driven scaling algorithms in cloud management systems for guaranteeing performance invariants of distributed cloud applications, as opposed to using only reactive SLA-based VM-scaling algorithms.

Efficient Deployment of Mobile Detectors for Security Applications

We present a real-world problem that arises in security threat detection applications. The problem consists of deploying mobile detectors on moving units that follow predefined routes. Examples of such units are buses, coaches, and trolleys. Due to a limited budget not all available units can be equipped with a detector. The goal is to equip a subset of units such that the utility of the resulting coverage is maximized. Existing methods for detector deployment are designed to place detectors in fixed locations and are therefore not applicable to the problem considered here. We formulate the planning problem as a binary linear program and present a coverage heuristic for generating effective deployments in short CPU time. The heuristic has theoretical performance guarantees for important special cases of the problem. The effectiveness of the coverage heuristic is demonstrated in a computational analysis based on 28 instances that we derived from real-world data.

Direct electrospinning of 3D auricle-shaped scaffolds for tissue engineering applications.

Thirty-two poly(ε)caprolactone (PCL) scaffolds have been produced by electrospinning directly into an auricle-shaped mould and seeded with articular chondrocytes harvested from bovine ankle joints. After seeding, the auricle shaped constructs were cultured in vitro and analysed at days 1, 7, 14 and 21 for regional differences in total DNA, glycosaminoglycan (GAG) and collagen (COL) content as well as the expression of aggrecan (AGG), collagen type I and type II (COL1/2) and matrix metalloproteinase 3 and 13 (MMP3/13). Stress-relaxation indentation testing was performed to investigate regional mechanical properties of the electrospun constructs. Electrospinning into a conductive mould yielded stable 3D constructs both initially and for the whole in vitro culture period, with an equilibrium modulus in the MPa range. Rapid cell proliferation and COL accumulation was observed until week 3. Quantitative real time PCR analysis showed an initial increase in AGG, no change in COL2, a persistent increase in COL1, and only a slight decrease initially for MMP3. Electrospinning of fibrous scaffolds directly into an auricle-shape represents a promising option for auricular tissue engineering, as it can reduce the steps needed to achieve an implantable structure.