Abstract

An acyclic vertex coloring of a graph is a proper vertex coloring such that there are no bichromatic cycles. The acyclic chromatic number of G, denoted a (G), is the minimum number of colors required for acyclic vertex coloring of graph G. For a family F of graphs, the acyclic chromatic number of F, denoted by a (F), is defined as the maximum a (G) over all the graphs G∈ F. In this paper we show that a (F)= 8 where F is the family of graphs of maximum degree 5 and give a linear time algorithm to achieve this bound.

Abstract

This paper considers the question of how many colors a distributed graph coloring algorithm would need to use if it had only k rounds available, for any positive integer k. In our main result, we present an algorithm that runs in O(k) rounds for any k bounded below by ©(log log n) and bounded above by O(√log n), and uses O(a Å n1/k) colors to color a graph with arboricity a. This result is optimal since the palette size matches the lower bound of Barenboim and Elkin (PODC 2008). This result is achieved via the use of several new results developed in this paper on coloring graphs whose edges have been acyclically oriented. For example, suppose that G is an n-vertex, acyclically oriented graph with maximum out-degree Δo. We present an algorithm that, for any k ≥ 2 loglog n, runs in O(k) rounds on G to produce an (i) O(Δo)-coloring when Δo Δ ©(maxkn2/k2log1+1/kn, 2k) and an (ii) O(Δo Å n2/k2)-coloring when Δo ∈ Ω(maxk log1+1/kn, 2k). These results are useful in any setting where it is possible to efficiently compute acyclic orientations of a graph with Δo << Δ. We derive non-trivial bounds on the palette size even when k < 2 loglog n. Our main technical contributions can be summarized as: (i) developing a k-round version of the algorithm of Kothapalli et al. (IPDPS 2006) which computes an O(?)-coloring of a graph in O(√log n) rounds, and (ii) developing an oriented version of the Brooks-Vizing coloring result of Grable and Panconesi (SODA 1998).

Abstract

Pneumoconiosis, a lung disease caused by the inhalation of dust, is mainly diagnosed using chest radiographs. The effects of using contralateral symmetric (CS) information present in chest radiographs in the diagnosis of pneumoconiosis are studied using an eye tracking experimental study. The role of expertise and the influence of CS information on the performance of readers with different expertise level are also of interest. Experimental subjects ranging from novices & medical students to staff radiologists were presented with 17 double and 16 single lung images, and were asked to give profusion ratings for each lung zone. Eye movements and the time for their diagnosis were also recorded. Kruskal-Wallis test (χ2(6) = 13.38, p = .038), showed that the observer error (average sum of absolute differences) in double lung images differed significantly across the different expertise categories when considering all the participants. Wilcoxon-signed rank test indicated that the observer error was significantly higher for single-lung images (Z = 3.13, p < .001) than for the double-lung images for all the participants. Mann-Whitney test (U = 28, p = .038) showed that the differential error between single and double lung images is significantly higher in doctors [staff & residents] than in non-doctors [others]. Thus, Expertise & CS information plays a significant role in the diagnosis of pneumoconiosis. CS information helps in diagnosing pneumoconiosis by reducing the general tendency of giving less profusion ratings. Training and experience appear to play important roles in learning to use the CS information present in the chest radiographs.

Abstract

Automatic retinal image analysis is emerging as an important screening tool for early detection of eye diseases. Glaucoma is one of the most common causes of blindness. The manual examination of optic disk (OD) is a standard procedure used for detecting glaucoma. In this paper, we present an automatic OD parameterization technique based on segmented OD and cup regions obtained from monocular retinal images. A novel OD segmentation method is proposed which integrates the local image information around each point of interest in multidimensional feature space to provide robustness against variations found in and around the OD region. We also propose a novel cup segmentation method which is based on anatomical evidence such as vessel bends at the cup boundary, considered relevant by glaucoma experts. Bends in a vessel are robustly detected using a region of support concept, which automatically selects the right scale for analysis. A multi-stage strategy is employed to derive a reliable subset of vessel bends calledr-bends followed by a local spline fitting to derive the desired cup boundary. The method has been evaluated on 138 images comprising 33 normal and 105 glaucomatous images against three glaucoma experts. The obtained segmentation results show consistency in handling various geometric and photometric variations found across the dataset. The estimation error of the method or vertical cup-to-disk diameter ratio is 0.09/0.08 (mean/standard deviation) while for cup-to-disk area ratio it is 0.12/0.10. Overall,the obtained qualitative and quantitative results show effective-ness in both segmentation and subsequent OD parameterization for glaucoma assessment.

Abstract

Every year in the country innumerable number of life and property is getting lost in the disasters. Pre-disaster planning i.e., mitigation and preparedness can have a good impact on minimizing the post-disaster response i.e., emergency, rescue and rehabilitation. This also reduces tragedy and suffering to a great extent. Andhra Pradesh being 4th largest state in India by area of 2,75,608 km² and 5th largest in population with over 100 million and a density of 277 persons/km2 is spread over 23 districts. Although it lies in the central part of peninsular Indian shield it has prone to many disasters which caused large number of casualties and innumerable property loss. This paper discusses the disasters like cyclone, floods, drought, earthquakes, tsunami, fire, etc., with statistics relevant to each disaster. Finally, we recommend the effecient strategies for disaster risk mitigation.

Abstract

In the past there were many terrorist attacks on buildings. Also the threat of such kind of attacks is increasing day-by-day. After the progressive collapse of the Roman Point apartment, England in 1968, structural engineering research departments throughout the world forced to direct their research towards the progressive collapse of highrise buildings under abnormal loads. Many guidelines, standards and criteria were developed across the world. Such guidelines are necessary for construction of blast resistant buildings. However, in addition to these guidelines, it is necessary to understand the progressive collapse process of the building under the action of heavy impact load. In this paper, we studied the linear responses of different RC bare frames for different ranges and charge weights according to different blast loads. Initially, the blast loads over the frames are calculated for for different ranges and charge weights according to TM 5-1300 9. Later these loads are applied on the bare frames taken from the structures which are designed for the normal gravity and lateral loads. Four fames (one story one bay, three story one bay, five story one bay and ten story-three bays) are considered. For the purpose of the study, highly efficient numerical model AEM is used. Results clearly show that the even though the charge weight of the blast is increasing the response is not increasing linearly. Also the response is low for heavy structures compared to lighter structures.

Abstract

The world today has encountered with global warming and climate change. Besides other contributors, extraction of natural resources as building materials itself consume energy, cause environmental degradation and contribute to global warming. Buildings are the largest energy consumers and greenhouse gases emitters, both in the developed and developing countries. Urgent changes are therefore required relating to energy saving, emissions control, production and application of materials. Immediate suggestion related to use of renewable resources, and to recycling and reuse of building materials is necessary. This paper describes how much a typical building is contributing to global warming by releasing the carbon dioxide emission. And how the architects and building designers can decrease the amount of carbon footprint emitted from the building materials. As a case study a 3-story building made of commonly used materials; concrete, brick, stone and glass has been selected. Total quantity of carbon emission is estimated and finally suggestions are given to reduce carbon dioxide emission.

Abstract

The main objective of the project is Vulnerability Assessment of Port buildings in different port regions along west coast of India. It includes development of earthquake scenario and fragility curves, which describes in detail the effects and consequences of a hypothetical earthquake at that region. In this paper the plan, elevation and design details of the port building near the Pipavav port is mentioned. For performance evaluation, a 3-dimensional model of the structure was generated. Analysis and design is performed on the structure. Pushover analysis is done for each earthquake data, and the graph is plotted for displacement vs load and displacement vs stiffness. Hence stiffness degradation for each earthquake data for its maximum displacement is determined and fragility curve is developed for the port building. A 3-dimensional model of the structure was modeled in STAAD.Pro and seismic base shear is calculated for the structure using the IScode 1893 (Part1:2002) and the linear time history analysis is carried out on the structure.

Abstract

Analysis and design of high-rise buildings for lateral load such as wind load and earthquake are the major issues which are playing significant role in recent decades .This paper describes a recent application of the computational fluid dynamics technique for wind analysis. Conventional wind analysis suggests wind tunnel experiment for arriving at the wind forces for a given structural form. As a case study a regural 38-story high-rise building (Jamieson place, Calgary Canada) made of concrete with shear wall ,built in downtown Calgary 2010 is selected. It is assumed that the building is located in highly seismic area. The design objective was to develop most cost-effective structural system while meeting building functionality goals and adhering to code requirement. The main structural design issues considered in this building are reviewed: Static analysis, Dynamic Analysis, Wind Analysis and Stability Analysis. Initial static and dynamic analysis is conducted in SAP and later wind analysis is conducted in Ansys as opposed to wind tunnel experiments. The building model is modeled in Ansys workbench and then the mesh file is imported to Ansys CFX for CFD simulation and analysis. After CFD analysis the wind forces on the building model are extracted in Ansys CFX-Post and imported to the structural model in SAP 2000 for the structural analysis.

Abstract

Presently India is home for about 1.2 billion people. This suggests that about 300 million houses are necessary to house them. According to National Housing Policy 2007 (NUHHP, 2007), the housing shortage is estimated to be about 25 million. And according to 2001 Census (Census 2001), Indian urban population constitutes 27.8%. However, it is increasing at an alarming rate of 4% per year. Further, population in India is distributed unevenly with minimum of 50 persons per km2 in some districts and upto 14000 persons per km2 in some other districts. Rural districts have upto 100 houses per km2 , towns 1000-1500 houses per km2 , cities 1500-2500 houses per km2 and urban centres and metros have as high as 7000 houses per km2. In addition, there is a great shift of population from rural to urban areas thus increasing the densities of population in urban areas. The number and proportion of cities with a population of one million or more has grown significantly in recent decades. From 12 in 1981 with 26.8% share of the total population, the number of million-plus cities has increased to 35 in 2001 with 37% share of the total urban population. On the other hand the dominant materials of choice for building were