Speeding up SOR Solvers for Constraint-based GUIs with a Warm-Start Strategy

Many computer programs have graphical user interfaces (GUIs), which need good layout to make efficient use of the available screen real estate. Most GUIs do not have a fixed layout, but are resizable and able to adapt themselves. Constraints are a powerful tool for specifying adaptable GUI layouts: they are used to specify a layout in a general form, and a constraint solver is used to find a satisfying concrete layout, e.g.\ for a specific GUI size. The constraint solver has to calculate a new layout every time a GUI is resized or changed, so it needs to be efficient to ensure a good user experience. One approach for constraint solvers is based on the Gauss-Seidel algorithm and successive over-relaxation (SOR). Our observation is that a solution after resizing or changing is similar in structure to a previous solution. Thus, our hypothesis is that we can increase the computational performance of an SOR-based constraint solver if we reuse the solution of a previous layout to warm-start the solving of a new layout. In this paper we report on experiments to test this hypothesis experimentally for three common use cases: big-step resizing, small-step resizing and constraint change. In our experiments, we measured the solving time for randomly generated GUI layout specifications of various sizes. For all three cases we found that the performance is improved if an existing solution is used as a starting solution for a new layout

Hand Detection using HSV Model

Natural Human Computer Interaction (HCI) is the demand of today’s technology oriented world. Detecting and tracking of face and hands are important for gesture recognition. Skin detection is a very popular and useful technique for detecting and tracking human-body parts. It has been much attention mainly because of its vast range of applications such as, face detection and tracking, naked people detection, hand detection and tracking, people retrieval in databases and Internet, etc. Many models and algorithms are being used for detection of face, hand and its gesture. Hand detection using model or classification is to build a decision rule that will discriminate between skin and non-skin pixels. Identifying skin color pixels involves finding the range of values for which most skin pixels would fall in a given color space. All external factors will be eliminated to detect the hand and its color in the image in complex background. Keywords: image segmentation, hand detection, hci, computer vision, RGB, HS

Optimising HYBRIDJOIN to Process Semi-Stream Data in Near-real-time Data Warehousing

Near-real-time data warehousing plays an essential role for decision making in organizations where latest data is to be fed from various data sources on near-real-time basis. The stream of sales data coming from data sources needs to be transformed to the data warehouse format using disk-based master data. This transformation process is a challenging task due to slow disk access rate as compare to the fast stream data. For this purpose, an adaptive semi-stream join algorithm called HYBRIDJOIN (Hybrid Join) is presented in the literature. The algorithm uses a single buffer to load partitions from the master data. Therefore, the algorithm has to wait until the next disk partition overwrites the existing partition in the buffer. As the cost of loading the disk partition into the buffer is a major cost in the total algorithm’s processing cost, this leaves the performance of the algorithm sub-optimal. This paper presents optimisation of existing HYBRIDJOIN by introducing another buffer. This enables the algorithm to load the second buffer while the first one is under join execution. This reduces the time that the algorithm wait for loading of master data partition and consequently, this improves the performance of the algorithm significantly

Kaczmarz Algorithm with Soft Constraints for User Interface Layout

The Kaczmarz method is an iterative method for solving large systems of equations that projects iterates orthogonally onto the solution space of each equation. In contrast to direct methods such as Gaussian elimination or QR-factorization, this algorithm is efficient for problems with sparse matrices, as they appear in constraint-based user interface (UI) layout specifications. However, the Kaczmarz method as described in the literature has its limitations: it considers only equality constraints and does not support soft constraints, which makes it inapplicable to the UI layout problem. In this paper we extend the Kaczmarz method for solving specifications containing soft constraints, using the prioritized IIS detection algorithm. Furthermore, the performance and convergence of the proposed algorithms are evaluated empirically using randomly generated UI layout specifications of various sizes. The results show that these methods offer improvements in performance over standard methods like Matlab\u27s LINPROG, a well-known efficient linear programming solver

Selective screening for organic acidurias and amino acidopathies in Pakistani children

Objective: To determine the frequency of organic acidurais (OA) and amino acidopathies (AA) in selected high-risk patients screened in two years.Study Design: Retrospective Observational study.Place and Duration of Study: The Aga Khan University Hospital (AKUH), Karachi, from January 2013 to December 2014.Methodology: Patients with OA and AA were included in the study and patients with IMDs other than OA and AA were excluded. Amino acids and organic acids were analyzed on high performance liquid chromatography and gas chromatography-mass spectrometry respectively. Clinical data and chromatograms of patients screened for IMDs were reviewed by chemical pathologist and metabolic physician.Results: Eighty-eight cases (4.7%) were diagnosed including 41 OA (46.5%), 28 AA (31.8%) and 19 others (21.5%) from 1,866 specimens analyzed. Median age of the patients was 1.1 years, with high consanguinity rate (64.8%). Among OA, methyl CoA mutase deficiency was diagnosed in 9 (10.2%) and was suspected in 2 (2.3%) cases. Five (5.7%) cases of MHBD (2-methyl-3-hydroxybutyryl-CoA), 4 (4.5%) each of PPA (propionic aciduria) and HMG-CoA lyase deficiency, 3 (3.4%) cases each of IVA (isovaleric aciduria), multiple carboxylase deficiency, fructose-1, 6-biphosphatase deficiency, fumarase deficiency, GA-1 (glutaric aciduria type 1) and 2 (2.3%) cases of EMA (ethyl-malonic aciduria). AA included 8 (9.1%) cases of MSUD (maple syrup urine disease), 6 (6.8%) cases of CBS (cystathionine beta-synthetase) and UCDs (urea cycle disorders) each, 5 (5.7%) cases of hyperphenylalaninemia and 3 (3.4%) cases of hyperprolinemia were reported. Other inherited metabolic disorders included: 9 (10.2%) cases of intracellular cobalamin defects, 2 (2.3%) cases each of alkaptonuria, Canavan\u27s disease, SUCL (succinate CoA ligase) deficiency, and 1 (1.1%) case each of DPD (dihydropyrimidine) deficiency, GA-2, NKH (non-ketotic hyperglycinemia), AADC (aromatic amino acid decarboxylase) deficiency.Conclusion: This study presents frequency of OA and AA in the high-risk Pakistani pediatric population analyzed locally