Vehicle Transactions

Automatic liver tumor segmentation from 3D Computed Tomography (CT) is a necessary prerequisite in the interventions of hepatic abnormalities and surgery planning. However, accurate liver tumor segmentation remains challenging due to the large variability of tumor sizes and inhomogeneous texture. Recent advances based on Fully Convolutional Network (FCN) in liver tumor segmentation draw on success of learning discriminative multi-level features. In this paper, we propose a Deep Attentive Refinement Network (DARN) for improved liver tumor segmentation from CT volumes by fully exploiting both low and high level features embedded in different layers of FCN. Different from existing works, we exploit attention mechanism to leverage the relation of different levels of features encoded in different layers of FCN. Specifically, we introduce a Semantic Attention Refinement (SemRef) module to selectively emphasize global semantic information in low level features with the guidance of high level ones, and a Spatial Attention Refinement (SpaRef) module to adaptively enhance spatial details in high level features with the guidance of low level ones. We evaluate our network on the public MICCAI 2017 Liver Tumor Segmentation Challenge dataset (LiTS dataset) and it achieves state-of-the-art performance. The proposed refinement modules are an effective strategy to exploit multi-level features and has great potential to generalize to other medical image segmentation tasks.

MAS have already more than proved their effectiveness while dealing with high level distributed problems, but some domains (usually low level ones) are still reluctant to their use, usually on a performance basis. UAV’s multisensor integration systems take information coming from different sensors and integrate them into one global positioning solution, with a pre-analyzed fixed data fusion architecture topology in a changing environment. In this paper we will propose a novel adaptative MAS data fusion architecture for this problem, able to change its topology according to its conditions, and thus effectively improving the overall quality of the system.

Determining the state of cloudiness at night is always a problem, especially at low levels of light pollution. This paper presents an innovative method of assessing the cloudiness of the night sky solely on the basis of all-night measurements of the brightness of the sky using generally available SQM meters. Using the numerical method of calculating the discrete derivative of the overnight brightness of the night sky from time it is possible not only to distinguish a cloudless sky from a cloudy one, but even to distinguish the high level clouds from medium and low level ones. Full Text: PDF ReferencesKyba C.C.M., Ruhtz T., Fischer J., Hölker F., Cloud Coverage Acts as an Amplifier for Ecological Light Pollution in Urban Ecosystems, PLoS ONE, vol. 6, no. 3, 2011, e17307. CrossRef Ściężor T., The impact of clouds on the brightness of the night sky, to be published in Journal of Quantitative Spectroscopy and Radiative Transfer, 2020 CrossRef Ściężor T., Kubala M., Kaszowski W., Light Pollution of the Mountain Areas in Poland, Archives of Environmental Protection, Vol.38, No.4, 2012, pp. 59-69. CrossRef Crawford D.L., Photometry: terminology and units in the lighting and astronomical sciences, The Observatory, vol. 117, 1997, pp. 14-18. DirectLink Ściężor T., Kubala M., Particulate matter as an amplifier for astronomical light pollution, Monthly Notices of the Royal Astronomical Society, vol. 444, no. 3, 2014, pp. 2487-2493. CrossRef

The paper proposes a conceptual model for describing and managing system development projects. The model provides a structured way to subdivide projects into tasks and a tool for measuring a priori the level of control needed to manage projects in information system and other areas. A Project Basic Unit (PBU) is defined as the main building block used to describe various levels of a project hierarchy. Project phasing, the subdivision of higher PBUs into lower level ones, is investigated. Criteria for project phasing which is an important element of managing projects, are outlined and discussed. The area of project control where one person performs more than one project role, called coresidence, is also presented. This phenomenon is a frequent cause of lack of control and malfunctions in system development projects.

Collision Probability with Gaussian Mixture Orbit Uncertainty

Non-Interference is an information flow security property which aims to protect confidential data by ensuring the complete absence of any information flow from high level entities to low level ones. However, this requirement is too demanding when dealing with real applications: indeed, no real policy ever guarantees a total absence of information flow. In order to deal with real applications, it is often necessary to allow mechanisms for downgrading or declassifying information such as information filters and channel control.In this paper we generalize the notion of Persistent Stochastic Non-Interference (PSNI) in order to allow information to flow from a higher to a lower security level through a downgrader. We introduce the notion of Delimited Persistent Stochastic Non-Interference (D_PSNI) and provide two characterizations of it, one expressed in terms of bisimulation-like equivalence checks and another one formulated through unwinding conditions. Then we prove some compositionality properties. Finally, we present a decision algorithm and discuss its complexity.

3D reconstruction of objects via Shape from Motion (SFM) has made great strides recently. Utilizing images from a variety of poses, objects can be reconstructed in 3D without knowing a priori the camera pose. These feature points can then be bundled together to create large scale scene reconstructions automatically. A shortcoming of current methods of SFM reconstruction is in dealing with specular or flat low feature surfaces. The inability of SFM to handle these places creates holes in a 3D reconstruction. This can cause problems when the 3D reconstruction is used for proximity detection and collision avoidance by a space vehicle working around another space vehicle. As such, we would like the automatic ability to recognize when a hole in a 3D reconstruction is in fact not a hole, but is a place where reconstruction has failed. Once we know about such a location, methods can be used to try to either more vigorously fill in that region or to instruct a space vehicle to proceed with more caution around that area. Detecting such areas in earth orbiting objects is non-trivial since we need to parse out complex vehicle features from complex earth features, particularly when the observing vehicle is overhead the target vehicle. To do this, we have created a Space Object Classifier and Segmenter (SOCS) hole finder. The general principle we use is to classify image features into three categories (earth, man-made, space). Classified regions are then clustered into probabilistic regions which can then be segmented out. Our categorization method uses an augmentation of a state of the art bag of visual words method for object categorization. This method works by first extracting PHOW (dense SIFT like) features which are computed over an image and then quantized via KD Tree. The quantization results are then binned into histograms and results classified by the PEGASOS support vector machine solver. This gives a probability that a patch in the image corresponds to one of three categories: Earth, Man-Made or Space. Here man-made refers to artificial objects in space. To categorize a whole image, a common sliding window protocol is used. Here we utilized 90 high resolution images from space shuttle servicing missions of the international space station. We extracted 9000 128x128 patches from the images, then we hand sorted them into one of three categories. We then trained our categorizer on a subset of 6000 patches. Testing on 3000 testing patches yielded 96.8% accuracy. This is basically good enough because detection returns a probabilistic score (e.g. p of man-made). Detections can then be spatially pooled to smooth out statistical blips. Spatial pooling can be done by creating a three channel (dimension) image where each channel is the probability of each of the three classes at that location in the image. The probability image can then be segmented or co-segmented with the visible image using a classical segmentation method such as Mean Shift. This yields contiguous regions of classified image. Holes can be detected when SFM does not fill in a region segmented as man-made. Results are shown of the SOCS implementation finding and segmenting man-made objects in pictures containing space vehicles very different from the training set such as Skylab, the Hubble space telescope or the Death Star.

In this paper, an algorithm for automatic extraction of DC biasing point towards generation of design plans is presented. Initially, the circuit is described as a hierarchy of modules and devices inside our dedicated framework CAIRO+. Electrical information is propagated from higher level modules, to lower level ones, till reaching the device level. During navigation through the hierarchy, a dependency subgraph is generated for each device and module. Each subgraph expresses electrical dependencies by choosing among a set of predefined sizing operators. To obtain a final directed acyclic graph, existing graph directed cycles are detected and removed. The resulting graph represents the complete sizing procedure for the analog IP. The calculated biasing point is compared against operating point simulation. The algorithm is successfully applied to two analog IPs: single-ended two-stages output transconductance amplifier and differential cascode current-mode integrator

The adoption and entering into force of the 1975 Convention on Registration of Objects Launched into Outer Space (also known as the Registration Convention) was another achievement in expanding and strengthening the corpus iuris spatialis. It was the fourth treaty negotiated by the member states of the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) and it represents a lex specialis to the Outer Space Treaty (OST), elaborating further Articles V, VIII, and XI of the OST. Article V OST deals with safe and prompt return of astronauts in case of distress or emergency landing to the state of registry of their space vehicle, which is then further defined in the Registration Convention. Article VIII OST only implied registration and provided for the consequences thereof, namely in respect of exercising jurisdiction and control over a registered space object. However, the Registration Convention specified the ensuing obligations and regulated the necessary practical steps of space objects registration. The Registration Convention also complements and strengthens Article XI OST, which stipulates an obligation of state parties to inform the secretary-general of the nature, conduct, locations, and results of their space activities in order to promote international cooperation. The prevailing purposes of the Registration Convention is the clarification of “jurisdiction and control” as a comprehensive concept mentioned in Article VIII OST. In addition to its overriding objective, the Registration Convention also contributes to the promotion and the exploration and use of outer space for peaceful purposes. Establishing and maintaining a public register reduces the possibility of the existence of unidentified space objects and thereby lowers the risk of putting, for example, weapons of mass destruction secretly into orbit. Notwithstanding these important objectives, the negotiation history of the Convention and its lower number of ratification compared to the previous three space treaties testify to the numerous challenges that surround registration. The mandatory marking of space objects was one of the most heated points of debate between member states during the drafting of the Convention in the 1970s. Member states had conflicting views, depending on whether they were launching states or potential victims of launch failures. Additionally, questions on whether there should be one central or several registers and whether the type of information to be registered should be obligatory or optional were also pivotal in the discussion. It took five years of negotiation for member states to reach compromises and to adopt the Registration Convention, containing 12 articles. The articles covered issues ranging from registration procedure and different registries to amendments and withdrawal from the Convention. In addition, the following novelties were introduced: a new definition on “state of registry” was included; the “Moscow formula” was abandoned as the depositary was moved to the UN; and the “in five years review” clause found in Article X signified that the drafters were anticipating that technological developments could have such an impact on the Convention’s provisions that shorter time span between reviews were required than in previous space treaties. Despite the Convention’s novelties and its objective to protect the attribution of jurisdiction and control on the basis of a registry, as well as to ensure the rights provided in the Liability Convention and the Rescue and Return Agreement by offering means to identify space objects, the articles dealing with joint launch registration and registration by Intergovernmental Organizations (IGOs) are seen as weakening jurisdiction and control concept. Due to the fact that jurisdiction and control stay only with the state of registry, the other launching states may only conclude appropriate agreements to retain any of these rights. Thus, international responsibility and liability remain with all the launching states, but jurisdiction and control only with the state of registry. Furthermore, in the case of an IGO, the IGO does not have the sovereign authority to exercise jurisdiction and control, thereby raising the question who could do so instead of or on behalf of an IGO. In this regard, the Convention leaves important areas unregulated. In the following years, there were proposals to expand the Registration Convention to encompass other subject matters such as financial interests of assets in outer space; however, up until today, these issues remain regulated only by the UNIDROIT Space Assets Protocol.

view Abstract Citations (107) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Nature of Solar Hydrogen Vortices Richardson, R. S. Abstract The hydrogen vortices surrounding spot-groups have been explained by the existence of magnetic fields produced by charged particles whirled around the spot at a low level, or as hydrodynamical vortices whose form depends upon how the gases are flowing into or out of the spot. It is possible to test these ideas if we are allowed to assume that the charged particles in the low- level whirl always have the same sign. For then all spots with the same polarity must also have the same direction of whirl. Furthermore, when the reversal of polarity occurs at sunspot minimum, there should be a reversal in the direction of whirl. Hale applied this test to the best hydrogen vortices observed from 1908 to 1924 and was unable to find any relationship between the polarity and the direction of whirl. But since about 8o per cent of the whirls were in the same direction as terrestrial cyclones, he concluded that the observations favored the hydrodynamical, rather than the electromagnetic, hypothesis. This test has been repeated, using all the observations from 1908 to 1939, extending over four sunspot cycles. The results obtained agree closely with those of Hale. Evidently, the direction the vortex takes is determined primarily by the solar rotation. Estimates were also made of the degree of curvature in the vortices. Closely wound spirals are rare; open ones, far more numerous Publication: The Astrophysical Journal Pub Date: January 1941 DOI: 10.1086/144238 Bibcode: 1941ApJ....93...24R full text sources ADS | Related Materials (1) Reprint: 1941CMWCI.639....1R

Space sail liner

We present a new software technology for on-line performance analysis and visualization of complex parallel and distributed systems. Often heterogeneous, these systems need capabilities for flexible integration and configuration of performance analysis and visualization. Our technology is based on an object-oriented framework for rapid prototyping and development of distributable visual objects. The visual objects consist of two levels, a platform/device-specific low level, and an analysis- and visualization-specific high level. We have developed a very high-level, markup language, called VOML, and a compiler for component-based development of high-level visual objects. The VOML is based on a software architecture for on-line event processing and performance visualization called EPIRA. The technology lends itself to constructing high-level visual objects from globally distributed component definitions. We present details of the technology and tools used, and show how an example visual object can be rapidly prototyped from several reusable components.

A theoretical model is developed to predict fluctuations in traffic noise due to statistical variation in properties of highway traffic, including differences in vehicle type, variations in individual vehicle emissions, clustering of vehicles by vehicle type, and variations in vehicle spacings within and between platoons. Traffic flow is described by a Markov renewal process (MRP), and the noise heard by an off-highway observer as a filtered MRP. Simple formulas for the arithmetic mean, variance, and covariance function of noise intensity are derived for the "shot noise" case (exponentially distributed spacings). A more complicated model with car and truck clustering is investigated numerically, based on traffic data given by Jewell for the southbound curb lane of U.S. 40 in Berkeley, California. Even with only a modest degree of truck clustering and variability in vehicle spacings and noise emission, the variation in noise level is much greater than usually predicted. The coefficient of variation of noise intensity is greater than unity at distances from the roadway less than 700 ft. Peak noise levels may thus be greatly underestimated (2 to 3 dB per highway lane) if these sources of variability are ignored.

The nature of expertise in industrial scheduling: Strategic and tactical processes, constraint and object management

<div class="htmlview paragraph">In the past decade, the space shuttle has been the key factor for the United States manned space exploration. In fact the space shuttle is the only means in which the United States government can send humans into space. However, the space shuttle's life-expectancy is due to expire around the year 2005. In preparation for the end of the space shuttle era, we, as a country, must decide what type of future space vehicle is appropriate to accomplish our future national goals in space.</div> <div class="htmlview paragraph">There are many public policy alternatives to the question: ‘What will replace the space shuttle?’ First, the United States could try a conservative approach to space exploration by developing and using an unmanned vehicle. Second, the government could opt for utility by developing a mixed fleet of launch vehicles. Third, the United States could try to modify and update the current space shuttles with new technology. Fourth, the United States could choose to invest its money in more ‘exotic’ space vehicle programs such as the Single-Stage-To-Orbit(SSTO) space plane and the Two-Stage-To-Orbit(TSTO) space plane. Lastly, the United States could try to initiate talks with other countries concerning an international space agency that could pool the finances and resources into one unified space program.</div> <div class="htmlview paragraph">In my final recommendation, I would first look into a possible international cooperation for future funding and operation of space transportation. However, if this first objective is unable to produce any type of cooperation within a couple of years, I would initiate a parallel future space vehicle program that would involve most of the modification of the space shuttle option and all of the mixed fleet option. Along with these main public policy recommendations, I also recommend some administrative suggestions that could prove vital in trying to carry out the public policy of future space vehicles.</div>