bluuebunny/crossref_metadata_2025 huggingface dataset:
Gastrocnemius Recession to Treat Isolated Foot Pain
Authors: Maskill John D. , Bohay Donald R. , Anderson John G.
Published: January 2010

Background: Gastrocnemius recession is performed to correct an isolated gastrocnemius equinus contracture of the ankle that may accompany foot and ankle pathology in the adult. It has been proposed that this equinus deformity leads to excessive strain throughout the foot, thus causing pain. This can manifest itself in the form of plantar fasciitis, metatarsalgia, posterior tibial tendon insufficiency, osteoarthritis, and foot ulcers. The purpose of this retrospective study was to review the efficacy of the gastrocnemius recession in providing pain relief for patients who have foot pain without structural abnormality who have failed conservative treatment and have an isolated gastrocnemius contracture. Materials and Methods: Twenty-nine patients (34 feet) who had chronic foot pain without any structural abnormality other than an isolated gastrocnemius contracture underwent a gastrocnemius recession and were available for follow up at an average of 19.5 (range, 7 to 44) months. The outcome measurements were related to pain relief (Visual Analog Scale) and patient satisfaction. Results: Preoperatively the average pain score was 8/10 which improved postoperatively to 2/10. Twenty-seven patients (93.1%) said they would recommend this procedure for isolated foot pain to a friend. Twenty-seven patients (93.1%) said they were satisfied with the results of the procedure. Twenty-three of 25 patients (92%) who had a unilateral procedure stated they would have the contralateral leg done if needed. Conclusion: Gastrocnemius recession was found to be an effective procedure when used to relieve recalcitrant foot pain in those patients with an isolated gastrocnemius contracture without deformity.

Level of Evidence: IV, Retrospective Case Series
Lambrinudi Arthrodesis with Posterior Tibialis Transfer in Adult Drop-Foot
Authors: Elsner Andreas , Barg Alexej , Stufkens Sjoerd A. , Hintermann Beat
Published: January 2010

Background: The adult drop-foot is one of the most disabling disorders that affects gait and quality of life. Despite orthoses and orthopaedic shoes, the disability often progresses. We have used the Lambrinudi arthrodesis to correct the bony component of drop-foot in association with a posterior tibial tendon transfer to provide lateral ankle stability and active dorsiflexion. This study presents results obtained in a consecutive series of 19 patients. Materials and Methods: Nineteen patients (mean age, 54.7 years) were treated for drop-foot with an osseous dorsiflexing procedure according to Lambrinudi's original technique and a posterior tibial tendon transfer to the lateral cuneiforme bone. Outcome measurements included extended radiographic and clinical investigations, including the AOFAS Hindfoot Score, SF-36, ROM and VAS. The mean followup time was 39 (range, 24 to 62) months. Results: The AOFAS Hindfoot Score improved from 38.9 preoperatively to 73.2 ( p < 0.001) at last followup, and the SF-36 scores improved from 38.3 to 70.5 ( p < 0.001). All patients were able to wear normal shoes at final followup. Conclusion: In this study of 19 patients, Lambrinudi arthrodesis combined with posterior tibial transfer proved to be a reliable and reproducible treatment for semi-rigid and rigid adult drop-foot caused by several aetiologies. It provided a stable correction of the adult drop-foot and high patient satisfaction in the mid- to long-term. In particular, it enabled the patient to wear normal shoes.

Level of Evidence: IV, Prospective Case Series
Bipolar Fresh Osteochondral Allograft of the Ankle
Authors: Giannini Sandro , Buda Roberto , Grigolo Brunella , Bevoni Roberto , Di Caprio Francesco , Ruffilli Alberto , Cavallo Marco , Desando Giovanna , Vannini Francesca
Published: January 2010

Background: Severe post-traumatic ankle arthritis poses a reconstructive challenge in the young and active patient. Bipolar fresh osteochondral allograft (BFOA) may represent an intriguing alternative to arthrodesis and prosthetic replacement. The aim of this study was to describe a lateral trans-malleolar technique for BFOA, and to evaluate the results in a case series. Materials and Methods: From 2004 to 2006, 32 patients, mean age of 36.8 ± 8.4 years, affected by ankle arthritis underwent BFOA with a mean followup of 31.2 months. The graft was prepared by specifically designed jigs, including the talus and the tibia with the medial malleolus. The host surfaces were prepared by the same jigs through a lateral approach. The graft was placed and fixed with twist-off screws. Patients were evaluated clinically and radiographically at 2, 4, and 6 month after operation, and at a minimum 24 months followup. A biopsy of the grafted areas was obtained from 7 patients at 1-year followup for histological and immunohistochemical examination. Results: Preoperative AOFAS score was 33.1 ± 10.9 and postoperatively 69.5 ± 19.4 ( p < 0.0005). Six failures occurred. Cartilage harvests showed hyaline-like histology with a normal collagen component but low proteoglycan presence and a disorganized structure. Samples were positive for MMP-1, MMP-13 and Capsase-3. Conclusion: The use of BFOA represents an intriguing alternative to arthrodesis or arthroplasty. We believe precise allograft sizing, stable fitting and fixation and delayed weightbearing were key factors for a successful outcome. Further research regarding the immunological behavior of transplanted cartilage is needed.

Level of Evidence: IV, Retrospective Case Series
Free Anterolateral Thigh Flap for Reconstruction of Car Tire Injuries of Children's Feet
Authors: Demirtas Yener , Neimetzade Tale , Kelahmetoglu Osman , Guneren Ethem
Published: January 2010

Background: Grade IV and V car tire injuries occurring in children cause extensive soft tissue defects with exposure or loss of tendons and bone on the dorsum of the foot. Free tissue transfer is indicated for reconstruction of these defects because of the limited local tissue available. We describe our management of high-grade car tire foot injuries in children with free anterolateral thigh flap (ALT). Materials and Methods: Five pre-school children with car tire injuries (one grade IV and four grade V) were treated with free ALT flap in the last 4 years. The mean age was 4.8 years. In four patients, immediate flap coverage after initial debridement was performed and delayed reconstruction was used as a secondary procedure in one patient. Results: One of the flaps was re-explored for hematoma evacuation and salvaged. All of the flaps survived completely and there were no donor site complications. None of the flaps required a debulking procedure and custom shoe wear has not been necessary in any of the patients. Minor gait abnormalities were detected in two of the patients. Conclusion: With minimal donor site morbidity, long vascular pedicle allowing anastomosis outside of the trauma zone, we believe free ALT flap provides the ideal soft tissue reconstruction for high grade car tire injuries of foot in children. ALT flap can be further thinned to adapt to the defect, contracts less than muscle flaps and contains a vascularized fascia which can be used for extensor tendon reconstruction.

Level of Evidence: IV, Retrospective Case Series
Comparison of Free Muscle and Perforator Skin Flaps for Soft Tissue Reconstruction of the Foot and Ankle
Authors: Demirtas Yener , Neimetzade Tale , Kelahmetoglu Osman , Guneren Ethem
Published: January 2010

Background: Free tissue transfer is generally required for reconstruction of soft-tissue defects of the foot and ankle region because of the limited local tissue available. This type of reconstruction may interfere with postoperative function and footwear if a bulky flap is used. Materials and Methods: Twenty-nine patients had free tissue transfers to the foot and ankle region during a period of 3 years. Sixteen had reconstruction with free anterolateral thigh perforator flaps (ALT) and 13 had reconstruction with free muscle flaps. The outcomes of both types of reconstructions were compared according to flap scores and complications, operative time, hospitalization, gait and shoewear problems. Results: The patients in the ALT group were younger compared with those of the free muscle flap group ( p = 0.022). The operative time and flap complication rate was significantly higher ( p = 0.007 and 0.040, respectively) in the ALT group. ALT was generally used for reconstruction of the dorsal foot, heel and plantar regions. Muscle flaps were preferred in the ankle region, where open fractures of the tibia and fibula were frequently present, and for the patients with increased risk of perioperative morbidity. Conclusion: Free ALT flap consisting of skin and adaptable subcutaneous tissue, both diminishes donor site morbidity and is ideally suited for most soft-tissue reconstruction of the dorsal foot, heel and plantar foot. Free muscle flaps, however, may offer relatively less complicated tissue transfers and are preferred at the ankle region in the presence of open tibia fractures, and in high risk patients to decrease the perioperative morbidity.

Level of Evidence: III, Retrospective Case Control Study
Reverse Sural Artery Flap for Reconstruction of Blast Injuries of the Foot and Ankle
Authors: Orr Justin , Kirk Kevin L. , Antunez Vincent , Ficke James
Published: January 2010

Background: The reverse sural artery fasciocutaneous flap is a versatile soft tissue coverage procedure for traumatic soft tissue defects of the distal tibia, ankle, and foot. War-related blast injuries represent a unique injury mechanism. There are no reports on use of this reconstructive flap in treating highly contaminated war-related musculoskeletal trauma of the foot and ankle. The current study presents results using this soft tissue coverage procedure in a subacute fashion to treat a population of war-related blast injuries. Materials and Methods: A retrospective chart study was performed to assess outcomes of ten consecutive patients with severe lower extremity musculoskeletal trauma requiring soft tissue coverage using reverse sural artery fasciocutaneous flaps. Average patient age was 27.2 years. All injuries occurred between 2003 and 2008 as a result of severe war-related blast injuries. Results: All ten patients sustained Gustilo Type IIIB open fractures within the zones of injuries secondary to high energy blasts. Average time to flap coverage was 37 (range, 18 to 112) days post-injury. All ten flaps were well-healed at 12 weeks postoperatively. Major complications included one nonunion, three deep infections with chronic osteomyelitis, and three late elective amputations unrelated to the viability of the flap. Conclusion: In appropriately selected patients with significant open bony and soft tissue trauma to the foot and ankle, the reverse sural artery fasciocutaneous flap should be considered as a viable first option for soft tissue coverage, even in cases of subacute coverage. Early coverage is preferable in cases of severe contamination and soft tissue destruction, but late coverage of distal lower extremity defects with a sural artery flap is possible with good outcomes.

Level of Evidence: IV, Retrospective Case Series
Implications for the Anatomy of the Flexor Hallucis Brevis Insertion
Authors: Hakim-Zargar Mariam , Aronow Michael S. , Gibson Lina , Obopilwe Eifho
Published: January 2010

Background: Excessive hallux proximal phalangeal base removal during first MTP resection arthroplasty, implant arthroplasty, or amputation can compromise the flexor hallucis brevis (FHB) insertion leading to first MTP joint plantarflexion weakness, cock-up toe deformity, and altered forefoot loading. Material and Methods: The insertional anatomy of the FHB tendon was measured in 30 fresh frozen cadaver specimens. The FHB was then cyclically loaded and bone sequentially removed from the proximal phalangeal base until specimen failure occurred. Results: The mean length of the lateral and medial FHB insertions measured 9.0 ± 0.6 mm and 8.0 ± 0.5 mm, respectively ( p < 0.0001). The mean width of the lateral and medial FHB insertions measured 7.1 ± 1.0 mm and 8.8 ± 1.4 mm, respectively ( p < 0.0001). FHB insertion length as a percentage of total proximal phalangeal length was 26% ± 3% medially and 30% ± 3% laterally. Twenty-two specimens failed at the FHB insertion site after an average of 7.8 ± 1.0 mm or 24% ± 3% of the total length of the proximal phalanx had been resected from the base. Conclusion: Six millimeters of bone or 20% of the proximal phalangeal length could be safely removed from the hallux proximal phalangeal base without compromising the integrity of the FHB insertion to a physiologic load. Retaining 10 mm of the hallux proximal phalangeal base during amputation would preserve the medial FHB insertion and sacrifice none to less than 0.4 mm of the lateral insertion in our specimens. Clinical Relevance: This study demonstrates how much hallux proximal phalangeal base can be resected during first MTP arthroplasty or needs to be retained during amputation to preserve FHB function.
Suture-Button Versus Screw Fixation of the Syndesmosis: A Biomechanical Analysis
Authors: Klitzman Robert , Zhao Heng , Zhang Li-Qun , Strohmeyer Greg , Vora Anand
Published: January 2010

Background: The treatment of ankle fractures with syndesmotic injuries associated with disruption of the deltoid ligament complex is controversial. The purpose of this study was to compare both the biomechanical and physiologic properties of suture-button fixation to the intact syndesmosis and screw fixation. Materials and Methods: Eight fresh frozen human cadaveric ankles were used in three different groups. One group had an intact syndesmosis and deltoid ligamentous complex and two groups had fixation of the syndesmosis after its disruption along with disruption of the deltoid ligaments. One fixation group used a suture-button and the other used a 3.5-mm tricortical syndesmotic screw. The syndesmotic gap after cycling at submaximal loads, laxity due to cycling, and fibular movement allowed in the sagittal plane were all measured and analyzed for statistical significance. Results: The syndesmotic gap after cycling was not significantly different between the intact group (9.1 mm) and the suture-button group (8.8 mm) ( p = 0.1509). The screw fixation group had a significantly smaller gap (7.9 mm) as compared to the other two groups (screw versus intact, p = 0.00004; screw versus suture-button, p = 0.0004). The intact group did not demonstrate a significant difference in laxity before (9.0 mm) and after (9.1 mm) cycling ( p = 0.0670), whereas the suture-button group did have a significant difference (before, 8.01 mm; after, 8.28 mm) ( p = 0.000251). The movement of the fibula in the sagittal plane was significantly greater in the suture-button group (3.17 mm) as compared to the intact group (2.77 mm) ( p = 0.00554). Screw fixation allowed significantly less fibular movement in the sagittal plane (1.16 mm) as compared to the intact ( p = 0.00014) and suturebutton ( p = 0.0000012) groups. Conclusion: Suture-button fixation maintained reduction after cycling with submaximal loads that compared favorably to the intact syndesmosis. It also allowed more physiologic movement of the fibula in the sagittal plane when compared to tricortical screw fixation. Clinical Relevance: Syndesmotic injury fixation has traditionally used screws to provide a rigid construct in which healing can take place. We believe a less rigid fixation method, such as suture-button fixation, provides a more physiologic type of healing of the syndesmosis.
Compression Forces of Internal and External Ankle Fixation Devices with Simulated Bone Resorption
Authors: Yakacki Christopher M. , Khalil Heidi F. , Dixon Sean A. , Gall Ken , Pacaccio Douglas J.
Published: January 2010

Background: Internal and external fixation techniques have been developed to provide rigidity and stability to a fusion site such as in tibiotalocalcaneal (TTC) arthrodesis. Compression of the fusion site plays an integral role in primary bone healing, though little work has been done to quantify the compressive force values of ankle fixation devices. Materials and Methods: Using synthetic and cadaveric bone models, a Newdeal/Integra PantaNail and DePuy VersaNail were tested as compressive intramedullary (IM) nails while an Encore True/Lok and an Ace-Fischer frame were tested as external fixators. Results: The PantaNail experienced maximum compressive loads of 1898 and 1255 N in synthetic and cadaveric constructs, respectively. The VersaNail experienced max compressive loads 388 N during installation. All IM nails tested experienced decreased compressive loads after removal of the external guide and instrumentation. The external fixators were loaded to approximately 1200 N in both synthetic and cadaveric constructs. The decrease in compressive load was recorded as a function of simulated fusion site bone resorption for all devices. The IM nails experienced a 90% reduction in load with less than 1 mm of resorption, while the external fixators held 50% load for over 4 mm of resorption. These data were verified using a simple constitutive model of IM nails and external fixators. Conclusion: Intramedullary nails are capable of generating compression, however, are unable to provide sustained compression for any considerable amount of resorption. External fixators are inherently capable of applying and sustaining greater amounts of compression. Clinical Relevance: Surgeons who perform TTC arthrodesis procedures should be aware of a device's ability to generate and sustain compression with respect to bone resorption.
Does Economic Growth in Nepal Cause Electricity Consumption
Authors: Dhungel Kamal Raj
Published: January 2010

This article examines the causal relationship between the per capita electricity consumption and the per capita real GDP (natural logarithm) during the period 1980-2006 in Nepal using co-integration and vector error correction model. According to the fi ndings, there is a unidirectional causality from per capita real GDP to per capita electricity consumption. Results show that per capita electricity consumption does not cause per capita real GDP. There is an important policy implication of the fi ndings. It is important because it has significant implications from the point of view of energy conservation, Green House Gas emission reduction and economic development. Energy conservation if the government or the power utility industry approves the appropriate national policy for entering into the practical action will enhance economic development in a sustainable basis.Key words: Co-integration; Unit-root; Causality; Energy conservation; Electricity consumption; Economic growth; NepalDOI: 10.3126/hn.v5i0.2485Hydro Nepal Vol. 5, July 2009 Page:37-41
Improvement in Performance and Emission Using Coconut Oil as a Diesel Substitute
Authors: Pandey Rajesh Kumar , Rehman A , Sarviya R M , Dixit Savita
Published: January 2010

Diesel engines, unlike their petrol counterparts, are omnivorous in fuel consumption habits and can easily run on vegetable oils without any major changes in the engine. Using raw oils in diesel engines led to such problems as the sticking of fuel injectors and piston rings due to choking, and the thickening of lubricating oils, resulting in clogging of filters, but these were overcome in a large measure by pre-conditioning of the fuel by a chemical process using methanol or ethanol called ‘Transesterification'. Coconut oil can be adapted as additive fuel for the existing bio diesel engines without major modifications. If diesel engines turn vegetarian in our country, which has a great potential for producing vegetable oils from the evergreen tropical forests and plantations, it will be a big achievement in terms of reducing the sky-rocketing petroleum bills! Edible coconut oil is subjected to Transesterification process to reduce its viscosity and resulting coconut methyl ester known as biodiesel used in 5 H.P. Single cylinder diesel engines. Result shows that heated B-100 blend gave better performance and produced lower smoke emission than other fuel blends.Key words: C.I. engine; Diesel; Biodiesel; Coconut oil; Engine emissionsDOI: 10.3126/hn.v5i0.2494Hydro Nepal Vol. 5, July 2009 Page:62-65
Continuous Departure Time Models
Authors: Gadda Shashank , Kockelman Kara M. , Damien Paul
Published: January 2010

Models of departure time presently rely on discrete choice or simple proportions across blocks of time within a 24-h day. Duration models allow for more flexible specifications to explain both unimodal (one-peak) and multimodal (multipeak) data, which are common in (aggregate) departure time data. This paper offers Bayesian estimates of continuous departure time models using accelerated failure time specifications for various trip purposes with several distributional specifications, including the log-normal, Weibull, Weibull with and without unobserved heterogeneity, and a mixture of normals. The home-based work and non–home-based trip models are created by means of unimodal distributions; the home-based nonwork trip departure times are modeled via a bimodal distribution. The results indicate that a Weibull with unobserved heterogeneity performs well among unimodal distributions, and that the multipeak profile can be modeled well with a mixture of normals.
Adding Mode Choice to Multiagent Transport Simulation
Authors: Rieser Marcel , Grether Dominik , Nagel Kai
Published: January 2010

It had been shown previously that so-called agent-based traffic micro-simulations could be used for dynamic traffic assignment, that is, iterative route adjustment, until either a Nash equilibrium or some steady state distribution between alternatives had been found. It was also shown that the same approach could be extended to (departure) time adjustment; that is, time adjustment and route adjustment could exist in the same iterative approach. In this paper it is shown that the approach can be extended to mode choice by forcing every synthetic traveler to consider every available mode. The implementation is verified with a test case for which an approximate solution can be analytically derived and for which it is shown that simulation and theory are consistent. It is then applied to a large-scale real-world example, the metropolitan Zurich, Switzerland, area, with about 1 million inhabitants. For this example, it is shown that the adaptive scheme, albeit seemingly simple, can outperform a more traditional approach that first computes mode choice on the basis of aggregate data and then runs the assignment for car traffic only. Sensitivity tests show that the model reacts in meaningful ways, in particular concerning the interaction between the time structure of activities and mode choice.
Heterogeneous Decision Rule Model of Mode Choice Incorporating Utility Maximization and Disutility Minimization
Authors: Srinivasan Karthik K. , Naidu G. Maheswara , Sutrala Tejaswi
Published: January 2010

With the advent of more flexible discrete choice models, the analysis of heterogeneity at the observed and unobserved levels is receiving increasing attention. However, heterogeneity in decision rules has hardly been investigated in the mode choice context. This study proposes a heterogeneous decision rule model of mode choice incorporating utility maximization and disutility minimization using empirical data from Chennai City, India. The two decision rules may yield different estimates of mode choice probabilities if the error structure is not symmetric. Therefore, a heterogeneous decision rule model is estimated by postulating separate choice behaviors for each decision segment. Because the decision rule remains latent, individuals are probabilistically assigned to the two segments. The membership propensity of belonging to each class is modeled by using a binary logit form. The performance of the proposed heterogeneous decision rule (HDR) model is compared with the pure utility maximization, pure disutility minimization, and heterogeneous latent class models. The results reveal that the HDR model outperforms these alternative specifications. Further, significant differences are observed across the decision segments for aggregate modal shares, intrinsic preference for different modes, sensitivity to modal attributes, role of subjective factors, and the effect of activity patterns and accessibility. Factors influencing the decision-segment membership propensity are also identified. These findings have important behavioral and practical implications for analysis and evaluation of travel demand management measures aimed at sustainable urban transportation systems, congestion mitigation, and transit improvement.
Evacuation Planning Using the Integrated System of Activity-Based Modeling and Dynamic Traffic Assignment
Authors: Lin Dung-Ying , Eluru Naveen , Waller S. Travis , Bhat Chandra R.
Published: January 2010

The occurrence of natural disasters in the coastal regions and numerous potential events in urban regions have drawn considerable attention among transportation stakeholders. Federal, state, and local officials need to be effectively prepared to address the challenges raised by an evacuation. The focus of this research effort is to develop a tool to study the repercussions of evacuation of an entire regional transportation network recognizing the human behavior element. Neglecting these seemingly chaotic traffic flow patterns would lead to inaccurate system assessment and predictions. The influences of evacuees’ locations in the urban region at the moment of emergency alert are studied. In addition, the locations of all members of the household are identified, and household member interactions are explicitly considered. Further, the accurate times the individuals enter the network to evacuate the study region are studied; times can vary according to where the other household members are located at that time and the travel time on the network to reach those locations. To accomplish the goals, the integration framework of activity-based modeling and dynamic traffic assignment is used to study the evacuation traffic flow patterns at the time of evacuation. Specifically, the paper describes the evacuation problem, discusses the utility of deploying the integrated module of activity-based modeling and dynamic traffic assignment for evacuation planning, and outlines the challenges in integrating these two tools.
Assessment of User Benefits in Presence of Random Taste Heterogeneity
Authors: Cherchi Elisabetta , Cirillo Cinzia , Polak John W.
Published: January 2010

The ultimate objective of most practical transport modeling is the evaluation of the economic impacts of alternative policy measures. During the past decade, significant advances have been made in the ability of operational models to accommodate flexible patterns of taste heterogeneity. The majority of applications use parametric distributions in which the parameters of the distribution are specified a priori. However, in reality individual tastes rarely follow a standard distribution, especially in the extremes of the distribution in which behavior is likely to differ substantially from that of the rest of the population. The major problem in these cases is the suitability of estimated models for determining economic welfare because they may yield erroneous or counterintuitive results. Recent research proposes using nonparametric models to capture randomness in individuals’ tastes, in which the shape of the unknown distribution is defined as part of the estimation process. But there is still no evidence regarding the implication of using these more advanced model structures for determining economic welfare. The aim of this paper is to investigate to what extent imposing a well-shaped distribution of individual tastes affects the appraisal of transport policy measures. In particular the focus is on random taste heterogeneity. With the use of simulated data, an investigation is done on how parametric and non-parametric models perform under different assumptions for true taste distributions. Finally, implications of the accuracy of alternative methods of computing benefit measures are critically analyzed.
Estimating Random Coefficient Logit Models with Full Covariance Matrix
Authors: Guevara Cristian Angelo , Cherchi Elisabetta , Moreno Matias
Published: January 2010

In the mixed logit model, random coefficients are estimated with the use of simulation methods to approximate the integral of the likelihood over the density of the coefficients. Although the model is very efficient, when it takes into account the full variance–covariance matrix of the coefficients, estimation problems may well arise and the simulation methods become impracticable as the number of coefficients increases–-the well-known curse of dimensionality. With simulated data in this research, the classical simulation approach of the random coefficient mixed logit model is compared with a new method proposed by Harding and Hausman, which is based on the Laplace approximation of the probability integrals to avoid simulation. The comparison carried out in this research differs from that of Harding and Hausman in two ways: ( a) observed choices are used instead of observed probabilities and ( b) the potential effect of the curse of dimensionality is formally explored by means of synthetic data. Contrary to Harding and Hausman's results, these experiments show that mixed logit is not only capable of estimating the variance–covariance matrix, but when both methods were estimable, it also always outperforms the Laplace approximation method. Estimates for the variance–covariance matrix obtained with both methods are, for almost all cases studied, remarkably poor. As expected, the Laplace approximation method is estimable for a larger number of random coefficients, arguably because the curse of dimensionality makes simulation in mixed logit impracticable. The paper concludes with a discussion of potential lines of improvement in the development of methods to estimate random coefficient models with full variance–covariance matrices.
Understanding and Accommodating Risk and Uncertainty in Toll Road Projects
Authors: Lemp Jason D. , Kockelman Kara M.
Published: January 2010

Forecasting traffic and toll revenues for new highway projects involves great uncertainty because of the inherent uncertainty in the models used to make forecasts. As private investment becomes more common in project financing, quantifying the levels of risk and uncertainty associated with such projects becomes critical. This paper represents a review of many key studies and reports dealing with uncertainty in traffic and revenue forecasts for highway projects. These studies found that tolled projects tend to suffer from substantial optimism bias in forecasts, with predicted traffic volumes exceeding actual volumes by 30% or more about half the time. Moreover, projects with greater uncertainty tend to overestimate Year 1 traffic volumes more and stabilize at lower final traffic volumes. But after one controls for added optimism bias in traffic forecasts (compared with nontolled projects), there is little difference in uncertainty levels between tolled and nontolled forecasts. A typical way to address uncertainty in traffic forecasts is through sensitivity testing via variations in key inputs and parameters. A more extensive and less arbitrary version of this, Monte Carlo simulation, can provide probability distributions of future traffic and revenue, although it tends to require many simulations, demanding greater computational effort and time, unless networks are streamlined. Nonetheless, if reasonable assumptions for model input and parameter distributions can be made, Monte Carlo simulation generates a variety of useful information and establishes the actual likelihood of loss (rather than more basic win–lose indicators from a limited set of stress tests).
Enhanced Destination Choice Models Incorporating Agglomeration Related to Trip Chaining While Controlling for Spatial Competition
Authors: Bernardin Vincent L. , Koppelman Frank , Boyce David
Published: January 2010

It is common knowledge that travelers often choose clusters or groups of nearby destinations that can be visited conveniently in a single tour. This propensity is becoming increasingly important in the context of rising fuel costs. However, gravity models, as well as most destination choice models, ignore these agglomeration effects and treat each trip or destination choice as independent. Some models have captured economies of agglomeration related to trip chaining through the use of accessibility variables. Accessibility variables, however, generally do not identify trip chaining effects uniquely, but measure differential spatial competition that arises because nearby destinations are generally better substitutes than distant ones. Because spatial competition effects generally dominate trip chaining agglomeration effects, models with a single accessibility variable have been called competing destinations models following Fotheringham. This paper presents an advance on Fotheringham's approach by introducing two distinct accessibility variables to represent agglomeration and spatial competition among destinations separately rather than their net effect. These new agglomerating and competing destination choice models were applied in Knoxville, Tennessee. The new models, which outperformed both gravity and competing destinations models, began to present a new alternative to activity-based models by allowing the incorporation of some of the most important trip chaining effects in trip-based travel demand models. For example, a sensitivity test showed that a new factory employing 1,000 workers would attract 125 new nonwork trips to the surrounding area on an average day as a result of stops on the way to and from work.
HIV contamination of commercial PCR enzymes raises the importance of quality control of low-cost in-house genotypic HIV drug resistance tests
Authors: Monleau Marjorie , Plantier Jean-Christophe , Peeters Martine
Published: January 2010

Background

Low-cost in-house technologies for genotypic drug resistance testing use reagents with quality labels for research only. Here, we report on the results of PCR amplifications in negative-controls that were observed in two independent laboratories.

Methods

Positive PCR amplifications of protease and reverse transcriptase fragments for genotypic drug resistance testing of HIV on dried blood and/or plasma spots were observed on negative-control samples and were analysed in detail by PCR and sequence and phylogenetic analyses to identify the origin of the PCR contamination.

Results

Detailed analysis revealed that the RT-PCR enzymes were contaminated with an HIV-based vector commercialized by the same company.

Conclusions

These observations show the need to implement quality control steps that verify for the absence of HIV in new reagent batches because this can significantly compromise molecular diagnosis of HIV and genotypic drug resistance tests using in-house protocols.
Global Stability Analysis of Multimedia Systems
Authors: Zhao Jie Min
Published: January 2010

A result of global stability for multimedia systems is given by means of the Liapunov functional method.
Design and Simulation of Distributed Vehicle Monitoring System Based on WebGIS
Authors: Yuan Gan Nan , Zhang Zhi
Published: January 2010

In this paper, a method is presented for designing the distributed vehicle monitoring system based on WebGIS, and also several important problems in system realization are discussed. On the basis of the software of MapXtreme for Java and the J2EE distributed three-layer model, the system is redeveloped with programming language of JSP and JBuilder, Tomcat and Jboss. Experiment and simulation results show that this system has good performance on vehicle monitoring and vehicle dispatch.
Simulating the Filtration Properties of Nonwoven Fabrics: Comparison of Artificial Neural Network, Statistical and Grey Models
Authors: Chen Ting , Zhao Shang Zhen , Wu Li Li
Published: January 2010

The artificial neural network, statistical and grey models are established for predicting the filtration properties of melt blown nonwoven fabrics from the processing parameters. The results show that the ANN model yields very accurate predictions and a reasonably good ANN model can be achieved with relatively few data points. The statistical model gives satisfactory prediction results for most cases, and the grey model needs to be improved for precise predictions. The results show great perspective of this research in the field of computer assisted design of melt blowing nonwoven technology.
Research on Active Services Component Library Based on Ontology
Authors: Wang Shun Yan , Ke You An , Wang Yan Wen
Published: January 2010

Active service is a kind of Web service which can be customized by customer’s requirement. The development of component technology provides foundation for the implementation of active services. Based on UCDL, the key technology of Local Component Resource Warehouse (LCRW) is expounded, the model of component library based on active service is constructed, the organization method by facet classification combined with ontology information classification is proposed, and the component retrieval based on Ontology Information is also proposed in view of facet retrieval.
Multi-Agent Order Selection and its Optimization Method with Evolution Algorithm
Authors: Zhang Li , Zhang Jie Wu , Ma Wei Jun
Published: January 2010

The rapid changes of market and outer surroundings have caused a dynamic and highly volatile business environment for the enterprise. Manufacturing organizations are seeking efficiency gains by competing via fast time-to-market and low production cost. An Autonomous Agent Network(ANN) Based Manufacturing System model is introduced, as well as the mathematics expression for the components of AAN model. The optimization algorithm based on evolution algorithm is used to solve the optimization problem of the model. Simulation results show that the architecture model and its optimization algorithm are effective to the problem.
Research on MES Domain Analysis Driven by Ontology
Authors: Long Wen
Published: January 2010

Manufacturing Execution System (MES) links plan management and workshop control in an enterprise, which is an integrative management and control system of workshop production oriented to manufacturing process. To overcome the difficulties of traditional software development method, development of MES based on component is adopted to prompt development efficiency and performance of MES, which can be more reconstructing, reuse, expansion and integration, and MES domain analysis driven by ontology is investigated in detail. MES domain analysis driven by ontology is feasible and efficient through developing a pharmaceutics MES which applied in a pharmaceutics manufacturing factory.
Research on Signal Demodulation Method of Silicon Micro-Machined Gyroscope
Authors: Yan Qing Wen , Zhang Fu Xue , Wu Li Feng , Sun Cheng Xiang
Published: January 2010

We report a silicon micro-machined gyroscope without the driven conformation. The output signal of the gyroscope contains the rolling, yawing, and pitching angular rates information. The principle of signal generation of the gyroscope is described with the equation, and the demodulation method of the gyroscope signals is illustrated by the experimental evidences. Toward the end, the key performances of the gyroscope are also presented.
Analysis of Reactive Pollutants Distribution in Damaging Street Canyon Architectures
Authors: Wang Peng , Mu Hai Lin
Published: January 2010

This study numerically investigates reactive pollutants (NO, NO2, and O3)
flow and dispersion in a street canyon with a canyon aspect ratio of one using a
simple chemical reaction mechanism. A line source for medium emissions of NOx was
considered in the presence of background O3 concentration. The contours of those
species (NO, NO2, and O3) was produced and the photo-stationary state defect was
calculated. It was found that the photo-stationary state defect was a sensitive indicator
of reactive mixing within the canyon and the greater the defect, the greater the local
state of chemical instability. High values were found near the roof level along the
downwind wall and low values were found at the ground near the upwind wall. The
results demonstrate that the anticorrosive materials should be positioned or construed
at the downwind side of the canyon.
Adaptive DCT Based Digital Watermarking Scheme
Authors: Feng Gui , Yang Yi Min
Published: January 2010

The paper proposes an adaptive digital watermarking scheme based on chaos sequence and DCT
transform. The scheme can choose the location for watermark inserting adaptively, and properly assign the
embedding intensity in different inserting locations according to the characteristic of human visual system
(HVS). On the other hand, this scheme combines chaos sequence and scrambling technique to improve the
ability to withstand various attacks. The experimental results show that, the method can basically satisfy
transparency and robustness requirement.
On the Global Stability Problem of Multimedia Systems
Authors: Zhao Jie Min
Published: January 2010

A global stability analysis for multimedia systems is given by means of the method of Liapunov functional.
Weighted Subgraph Mining Technology to Knowledge Discovery
Authors: Liu Bo
Published: January 2010

Currently there is such an increasing interest in discovering important patterns from graph data. A significant number of applications require effective and efficient manipulation of graph mining, such as being: (i) analysis of microarray data in bioinformatics, (ii) pattern discovery in a large graph representing a social network, (iii) analysis of transportation networks, (iv) community discovery in Web data. This paper concerned with subgraph discovery from weighted graph data that came from the educational context. The non-linear correlation technology was introduced and used in the mining process in the whole knowledge achieved. At last we have applied these methods in real course management datasets and found correspondent results for the educators.
An Improved Method for Mathematical Formula Extraction in Printed English and Chinese Documents
Authors: Tian Xue Dong , Liang Xiao
Published: January 2010

Accurately locating mathematical formulas in scientific documents is the basis of their recognition. The existing formula extraction methods mostly aim at the documents in one language, which is inadaptable to the documents in other languages. This paper describes an improved method to extract formulas not only in Chinese but also in English documents. First, using run-number as the features to distinguish the documents’ language; and then according to the difference between Chinese and English documents, corresponding features and parameters are chosen for the formula extraction. The experimental results show that this method can improve the robustness of formula extraction.
Diagonal Maximum Scatter Difference Analysis and its Application to Face Recognition
Authors: Wang Jian Guo , Zhang Tie Jun
Published: January 2010

Diagonal maximum scatter difference (DiaMSD) method for face recognition is proposed in this paper. This novel algorithm is developed based on two techniques, i.e., maximum scatter difference (MSD) and diagonal face images based projection. The DiaMSD method is not only computationally more efficient but also more accurate than the one dimensional (vector-based) MSD method in extracting the facial features for human face recognition. Extensive experiments are performed to test and evaluate the new algorithm using a subset of the FERET face databases. Experimental results show the effectiveness of the proposed method (DiaMSD).
Traffic Flow Forecasting Based on Chaos Neural Network
Authors: Zhang Yuan Yuan , Yang Shi Song , Cai Qing , Sun Peng
Published: January 2010

Traffic flow forecasting has become an emphasis question for discussion in traffic engineering domain and one kernel study in Intelligent Transportation System. After ensuring the traffic flow has the characteristic of chaos, traffic flow real data have been used to reconstruct phase space. Calculate the saturation phase space embedding dimension and maximal Lyapunov exponent. By above all, a chaos neural network model is constructed, which can make high precision short-term forecast for the nonlinear big-lagged system even by imperfect and variation inputs. At last, a forecasting example provides that the traffic flow forecasting based on chaos neural network is validity and feasibility.
Image Encryption Based on Genetic Engineering for Image Hiding
Authors: Zhou Shi Hua , Zhang Qiang , Wei Xiao Peng
Published: January 2010

Image encryption is one of the most important methods of image information hiding. A new image encryption method based on some techniques and knowledge of genetic engineering for image hiding is presented in this paper. This method is implemented by using modern biological techniques as tools and biological hard problems as main security basis to fully exert the special advantages. The keys are some substances of biological materials such as restriction endonuclease, polymerase and so on, the preparation flow and the experimental conditions. The analysis demonstrates that the image encryption algorithm is feasible and highly secure. Moreover, the size of the decrypted image is the same as the original image so that it can be applied for image hiding and be transmitted via the Internet.
Research of Displacement Measuring System Based on Capacitive Grating Sensor
Authors: Yu Guang Ping , Wang Shan Hui , Zhou Ying Gang
Published: January 2010

Capacitive grating sensor can be used to measure the length, as its capacitance changes with the shift difference. There are several measuring systems consisting of capacitive sensor, but all their basic principles are capacitive differential sensing. The structure, principles and characteristics of capacitive sensors are introduced in this paper. Especially, we designed a high-resolution electronic length measuring system based on Capacitive Grating Sensor. And the measurement error of the system and the reason are analysed. For this system, the measuring range is from 0 to 500mm, the resolution is 1um, the indication error is 5um, the measuring speed is 1m/s. Accurate measurement on account of large displacement is achieved with the system.
The Total Entropy Model of Fractal Supply Chain Network System
Authors: You Hong , Hao Zhong Xiao , Wang Quan
Published: January 2010

The entropies of structure, information and the effectiveness entropy between knowledge and organization structure are main entropy sources of supply chain network. Entropy model of fractal supply chain network organization structure is established. Fractal knowledge management network outside independently organization structure is built. Finally, the entropies of structure, information and the effectiveness entropy are summed. The model shows that fractal structure has prominent effect of dropping entropy.
Design and Simulation of an Improved Particle Swarm Optimization
Authors: Wei Jian Xiang , Sun Yue Hong
Published: January 2010

The particle swarm optimization (PSO) algorithm is a new population search strategy, which has exhibited good performance through well-known numerical test problems. However, it is easy to trap into local optimum because the population diversity becomes worse during the evolution. In order to overcome the shortcoming of the PSO, this paper proposes an improved PSO based on the symmetry distribution of the particle space position. From the research of particle movement in high dimensional space, we can see: the more symmetric of the particle distribution, the bigger probability can the algorithm be during converging to the global optimization solution. A novel population diversity function is put forward and an adjustment algorithm is put into the basic PSO. The steps of the proposed algorithm are given in detail. With two typical benchmark functions, the experimental results show the improved PSO has better convergence precision than the basic PSO.