An extended abstract: A heuristic repair method for constraint-satisfaction and scheduling problems

The work described in this paper was inspired by a surprisingly effective neural network developed for scheduling astronomical observations on the Hubble Space Telescope. Our heuristic constraint satisfaction problem (CSP) method was distilled from an analysis of the network. In the process of carrying out the analysis, we discovered that the effectiveness of the network has little to do with its connectionist implementation. Furthermore, the ideas employed in the network can be implemented very efficiently within a symbolic CSP framework. The symbolic implementation is extremely simple. It also has the advantage that several different search strategies can be employed, although we have found that hill-climbing methods are particularly well-suited for the applications that we have investigated. We begin the paper with a brief review of the neural network. Following this, we describe our symbolic method for heuristic repair

The min-conflicts heuristic: Experimental and theoretical results

This paper describes a simple heuristic method for solving large-scale constraint satisfaction and scheduling problems. Given an initial assignment for the variables in a problem, the method operates by searching through the space of possible repairs. The search is guided by an ordering heuristic, the min-conflicts heuristic, that attempts to minimize the number of constraint violations after each step. We demonstrate empirically that the method performs orders of magnitude better than traditional backtracking techniques on certain standard problems. For example, the one million queens problem can be solved rapidly using our approach. We also describe practical scheduling applications where the method has been successfully applied. A theoretical analysis is presented to explain why the method works so well on certain types of problems and to predict when it is likely to be most effective

A Social Network Analysis of Interest Group Contributions and Partisan Behavior in the 2006 House of Representatives

This project examines how interest groups create partisan connections among U.S. House members. Although the rise of ideologically motivated groups has been identified as a potential cause of legislative partisanship, there is very little research on how interest groups affect the nature of partisan coalitions. We consider how interest group donation strategies create connections between legislators and how the resulting networks affect the nature of lawmaking in the House. We use a combination exploratory social network analysis and traditional statistical methods to examine the contribution network and voting behavior of legislators in the 2006 House of Representatives. The results the interest groups create significant connectivity among legislators, particularly in a way that is consistent with support centralized partisan conflict. However, we find that the consequences of this relationship are complex|it sometimes supports partisan conflict and sometimes discourages it

A conceptual approach for estimating resilience to fuel shocks

We examine a conceptual approach to the estimation of resilience of transport systems to fuel shocks, i.e. a severe and long lasting reduction in the availability of fuel for motorised transport. Adaptive capacity is an element of resilience and is defined in the paper. There is currently no indicator of adaptive capacity of individuals in small geographies sensitive to a variety of policy measures, such as those affecting fitness, obesity, bicycle availability and bicycle infrastructure, whose impacts (at least in the short term) are on a smaller scale than large-scale land use and urban morphology change. We propose a conceptual approach for designing a method to quantify this indicator. The indicator shows the proportion of the population of areas who would have the capacity to commute to work principally by bicycle or walking following the shock. It assesses capacity grounded in current data and avoids as far as possible the need for speculation about the future. We believe this makes progress towards producing a good indicator with relatively un-controversial, transparent simplifying assumptions. The indicator can compare the resilience of different areas and can be updated over time

Air Launch: Examining Performance Potential of Various Configurations and Growth Options

The Advanced Concepts Office at NASA's George C. Marshall Space Flight Center conducted a high-level analysis of various air launch vehicle configurations, objectively determining maximum launch vehicle payload while considering carrier aircraft capabilities and given dimensional constraints. With the renewed interest in aerial launch of low-earth orbit payloads, referenced by programs such as Stratolaunch and Spaceship2, there exists a need to qualify the boundaries of the trade space, identify performance envelopes, and understand advantages and limiting factors of designing for maximum payload capability. Using the NASA/DARPA Horizontal Launch Study (HLS) Point Design 2 (PD-2) as a pointof- departure configuration, two independent design actions were undertaken. Both designs utilized a Boeing 747-400F as the carrier aircraft, LOX/RP-1 first stage and LOX/LH2 second stage. Each design was sized to meet dimensional and mass constraints while optimizing propellant loads and stage delta V splits. All concepts, when fully loaded, exceeded the allowable Gross Takeoff Weight (GTOW) of the aircraft platform. This excess mass was evaluated as propellant/fuel offload available for a potential in-flight propellant loading scenario. Results indicate many advantages such as payload delivery of approximately 47,000 lbm and significant mission flexibility including variable launch site inclination and launch window. However, in-flight cryogenic fluid transfer and carrier aircraft platform integration are substantial technical hurdles to the realization of such a system configuration

Kehadiran Bakteri Coliform Dalam Es Batu Pada Tiga Rumah Makan Ayam Goreng Siap Saji Di Bandung

Some reports have shown that ice cubes may contain Enterobacteriaceae bacteria. This descriptive, observational research aims to analyze the microbiological quality of the ice cubes served at three selected restaurants  (1,2,3).  Three  samples  of  ice  cubes  were  rinsed  with  steril  water,  left  melted,  and  diluted serially.  Each  diluted  sample  was  inoculated  into  MacConkey  Agar  and  EMB  Agar  with  pour  plate method duplo. The data collected were the number of colonies (interpreted as cfu or colony forming unit) of Escherichia coli and other Enterobacteriaceae bacteria. The species of selected colonies were identified by  biochemical reactions. The result showed that sample 1 contained 3 cfu/ml Escherichia coli and 5 cfu/ml Pseudomonas  sp.  Sample  2  contained  10  cfu/ml  Escherichia  coli  and  4  cfu/ml  Pseudomonas  sp.,  but sample 3 didn’t contain Escherichia coli and other Enterobacteriaceae bacteria members. It is concluded that ice cubes from restaurant 3 met the requirement for drinking water, whereas those from restaurants 1 and 2 did not. &nbsp

Akurasi Deteksi Mycobacterium Tuberculosis Dengan Teknik PCR Menggunakan “Primer X” Dibandingkan Dengan Pemeriksaan Mikroskopik (BTA) Dan Kultur Sputum Penderita Dengan Gejala Tuberkulosis Paru

Akhir-akhir ini, terjadi peningkatan jumlah penderita tuberkulosis. Guna pembe-rantasan penyakit TBC, diagnosis dan deteksi Mycobacterium tuberculosis menjadi amat penting. Deteksi tersebut dapat dilakukan dengan teknik Polymerase Chain Reaction (PCR), pemeriksaan mikroskopik, dan kultur bakteri. Tujuan penelitian ini adalah menilai sensitivitas, spesifisitas, dan akurasi deteksi Mycobacterium tuberculosis dalam sputum penderita TBC paru dengan teknik PCR dibandingkan pemeriksaan secara mikroskopik (Bakteri Tahan Asam/BTA) dan kultur bakteri TBC dalam sputum.Penelitian ini merupakan suatu uji diagnostik yang dirancang secara cross sectional. Penelitian dilakukan terhadap penderita TB paru di BP4 Jl Cibadak Bandung, mulai April 2004 sampai dengan Agustus 2004.Pemeriksaan sputum penderita dilakukan dengan tiga teknik pemeriksaan, yaitu dengan teknik PCR, pemeriksaan BTA secara mikroskopik, dan kultur bakteri.Dibandingkan dengan pemeriksaan Bakteri Tahan Asam secara mikroskospik, deteksi Mycobacterium tuberculosis dengan teknik PCR memiliki sensitivitas 30%, spesifisitas 80%, dan akurasi 47%. Uji kemaknaan dengan Mc Nemar memberikan hasil adanya perbedaan yang bermakna. (p < 0,01).Dibandingkan dengan metode kultur bakteri TBC, deteksi Mycobacterium tuberculosis dengan teknik PCR memiliki sensitivitas 65%, spesifisitas 40%, dan akurasi 57%. Uji kemaknaan dengan Mc Nemar memberikan hasil tidak adanya perbedaan yang bermakna. (p = 1,0). Dibandingkan dengan pemeriksaan Bakteri Tahan Asam secara mikroskospik, deteksi Mycobacterium tuberculosis dengan metode kultur bakteri TBC memiliki sensitivitas 31,6%, spesifisitas 81,8%, dan akurasi 50%. Uji kemaknaan dengan Mc Nemar memberikan hasil adanya perbedaan yang bermakna. (p < 0,01).Dengan demikian, dapat disimpulkan bahwa deteksi Mycobacterium tuberculosis dengan teknik PCR sama baiknya dengan kultur bakteri TBC, namun waktu pemeriksaan dengan teknik PCR lebih singkat dibandingkan dengan kultur bakteri TBC. Mycobacterium tuberculosis banyak tidak terdeteksi dengan pemeriksaan mikroskopik (BTA

Economic evidence for the prevention and treatment of atopic eczema: a protocol for a systematic review

Background: Eczema, synonymous with atopic eczema or atopic dermatitis, is a chronic skin disease that has a similar impact on health-related quality of life as other chronic diseases. The proposed research aims to provide a comprehensive systematic assessment of the economic evidence base available to inform economic modelling and decision making on interventions to prevent and treat eczema at any stage of the life course. Whilst the Global Resource of Eczema Trials (GREAT) database collects together the effectiveness evidence for eczema there is currently no such systematic resource on the economics of eczema. It is important to gain an overview of the current state of the art of economic methods in the field of eczema in order to strengthen the economic evidence base further. Methods/design: The proposed study is a systematic review of the economic evidence surrounding interventions for the prevention and treatment of eczema. Relevant search terms will be used to search MEDLINE, EMBASE, Database of Abstracts of Reviews of Effects, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, Health Technology Assessment, Cumulative Index to Nursing and Allied Health Literature, Econ Lit, Scopus, Cost-Effectiveness Analysis Registry and Web of Science in order to identify relevant evidence. To be eligible for inclusion studies will be primary empirical studies evaluating the cost, utility or full economic evaluation of interventions for preventing or treating eczema. Two reviewers will independently assess studies for eligibility and perform data abstraction. Evidence tables will be produced presenting details of study characteristics, costing methods, outcome methods and quality assessment. The methodological quality of studies will be assessed using accepted checklists. Discussion: The systematic review is being undertaken to identify the type of economic evidence available, summarise the results of the available economic evidence and critically appraise the quality of economic evidence currently available to inform future economic modelling and resource allocation decisions about interventions to prevent or treat eczema. We aim to use the review to offer guidance about how to gather economic evidence in studies of eczema and/or what further research is necessary in order to inform this

Impact of chromophores on colour appearance in a computational skin model

Early diagnosis of skin cancer offers the patient more favorable treatment options. Color fidelity of skin images is a major concern for dermatologists as adoption of digital dermatoscopes is increasing rapidly. Accurate color depiction of the lesion and surrounding skin are vital in diagnostic evaluation of a lesion. We previously introduced VCT-Derma, a pipeline for dermatological Virtual Clinical Trials (VCTs) including detailed and flexible models of human skin and lesions, which represent the patient in the entire dermatoscopy-based diagnostic process. However, those initial models of skin and lesions did not properly account for tissue colors. Our new skin model accounts for tissue color appearance by incorporating chromophores (e.g., melanin, blood) into the tissue model, and simulating the optical properties of the various skin layers. The physical properties of the skin and lesion were selected from clinically plausible values. The model and simulated dermatoscope images were created in open modelling software, assuming a linear camera model. We have assumed ambient white lighting, with a 6mm distance to the camera. Our model of color appearance was characterised by comparing the brightness of the lesion to its depth. The brightness of the lesion is compared through the variability of the mean gray values of a cropped region around the lesion. We compare two skin models, one without extensive chromophore content and one with. Our preliminary evaluation of increasing chromophore content shows promise based on the results presented here. Further refinement and validation of the model is ongoing