797 research outputs found
VARIABILITY OF BARBELL TRAJECTORY DURING SNATCH FOR AN ELITE YOUNG FEMALE WEIGHTLIFTER
The purpose of this study was to investigate the variability of the barbell trajectory for an elite young female weightlifter. One high speed camera (120Hz) was used to film the barbell trajectories of a female lifter during snatch. The subject was asked to lift different barbell mass from 65 to 80 kg (fourteen lifts in total), and thirteen successful lifts were analyzed. The barbell trajectories and movement pattern of different lifts were similar to the results of previous studies, and the barbell paths almost were overlapping for the heaviest four successful lifts. The coefficients of variation (CV) of four kinematic parameters of barbell trajectory were smaller than the results of previous studies. It can be concluded that this female weightlifter has a stable pattern of barbell trajectory under different barbell mass lifting
BIOMECHANICS OF STOP-JUMP LANDING AND IN-LINE SKATING JUMP LANDING
The purpose of this study was to identify the movement characteristics of lower extremities during stop-jump landing and in-line skating jump landing. Two subjects were asked to perform three jump landing tasks: stop-jump with barefoot (BF), stop-jump with ankle constrain (AC) and jump with in-line skating boots (IS). Landing movements in sagittal plane were recorded by one high speed camera. The activation of four muscles during landing was measured by EMG system. The kinematic results showed that most variables were significantly different between the three jump landing tasks, except for knee angle at ground contact. More activated rectus femoris and smaller knee flexion acceleration found in IS have been considered to be related the ACL injury. It can be concluded that in-line skating jump landing might have higher lower limbs injury risk
Using Hybrid Angle/Distance Information for Distributed Topology Control in Vehicular Sensor Networks
In a vehicular sensor network (VSN), the key design issue is how to organize vehicles effectively, such that the local network topology can be stabilized quickly. In this work, each vehicle with on-board sensors can be considered as a local controller associated with a group of communication members. In order to balance the load among the nodes and govern the local topology change, a group formation scheme using localized criteria is implemented. The proposed distributed topology control method focuses on reducing the rate of group member change and avoiding the unnecessary information exchange. Two major phases are sequentially applied to choose the group members of each vehicle using hybrid angle/distance information. The operation of Phase I is based on the concept of the cone-based method, which can select the desired vehicles quickly. Afterwards, the proposed time-slot method is further applied to stabilize the network topology. Given the network structure in Phase I, a routing scheme is presented in Phase II. The network behaviors are explored through simulation and analysis in a variety of scenarios. The results show that the proposed mechanism is a scalable and effective control framework for VSNs
Exploring the Identification of Expertise: An Experiment in a Computer Software Corporation
People recognize and express their expertise in several ways. In one way, workers can build personal profile to list their expertise. They recall their working experience and write some keyword terms in their personal profiles. In the other way, workers can build expertise in extracting from any documents they provided that includes studying documents, working documents or published papers. We want to know how the workers in the computer software corporation recognize and identify their expertise and explore the heuristics in identification of the expertise. We made an experiment comprised the above methods and invited 25 persons in a computer software corporation to participate and explore how they identify their expertise. During the experiment process, we found that (1) for most people, it’s hard to tell what expertise they completely have without any hint; (2) except these two ways, researchers or practitioners must innovate other methods to identify or elicit human’s expertise; (3) expertise in particular domain is rather than single term, but also multiple complex and related term sets; (4) expertise would be different with different audiences
A Novel Family of Cyst Proteins with Epidermal Growth Factor Repeats in Giardia lamblia
The biological goal of Giardia lamblia life cycle is differentiation into a cyst form (encystation) that can survive in the environment and infect a new host. Since cystic stages are key to transmission of parasites, this differentiation may be a target for interruption of the life cycle. Synthesis and assembly of the extracellular cyst wall are the major hallmarks of this important differentiation. During encystation, cyst wall structural proteins are coordinately synthesized and are mainly targeted to the cyst wall. However, only a few such proteins have been identified to date. In this study, we used a combination of bioinformatics and molecular approaches to identify new cyst structural proteins from G. lamblia and found a group of Epidermal Growth Factor (EGF)-like Repeats containing Cyst Proteins (EGFCPs). Interestingly, the levels of EGFCPs proteins increased significantly during encystation, which matches the characteristics of the Giardia cyst wall protein. Further characterization and localization studies suggest that EGFCPs may function like cyst wall proteins, involved in differentiation of G. lamblia trophozoites into cysts. Our results provide valuable information regarding the function of a new group of cyst proteins in parasite differentiation into cysts and help develop ways to interrupt the parasite life cycle
Is the Clinical Version of the Iowa Gambling Task Relevant for Assessing Choice Behavior in Cases of Internet Addiction?
Objective: A critical issue in research related to the Iowa gambling task (IGT) is the use of the alternative factors expected value and gain–loss frequency to distinguish between clinical cases and control groups. When the IGT has been used to examine cases of Internet addiction (IA), the literature reveals inconsistencies in the results. However, few studies have utilized the clinical version of IGT (cIGT) to examine IA cases. The present study aims to resolve previous inconsistencies and to examine the validity of the cIGT by comparing performances of controls with cases of Internet gaming disorder (IGD), a subtype of IA defined by the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders.Methods: The study recruited 23 participants with clinically diagnosed IGD and 38 age-matched control participants. Based on the basic assumptions of IGT and the gain–loss frequency viewpoint, a dependent variables analysis was carried out.Results: The results showed no statistical difference between the two groups in most performance indices and therefore support the findings of most IGT-IA studies; in particular, expected value and gain–loss frequency did not distinguish between the IGD cases and controls. However, the participants in both groups were influenced by the gain–loss frequency, revealing the existence of the prominent deck B phenomenon.Conclusion: The findings provide two possible interpretations. The first is that choice behavior deficits do not constitute a characteristic feature of individuals who have been diagnosed with IGD/IA. The second is that, as the cIGT was unable to distinguish the choice behavior of the IGD/IA participants from that of controls, the cIGT may not be relevant for assessing IGD based on the indices provided by the expected value and gain–loss frequency perspectives in the standard administration of IGT
Understanding Mobile Apps Continuance Usage Behavior and Habit: An Expectance-Confirmation Theory
With the growing development of information technology and the wireless telecommunication network nowadays, mobile devices have been expanding rapidly and have been emerging as important tools for consumers. Using m-services and applications (apps) on mobile devices becomes custom in people’s daily lives. This study proposes a theoretical model to explore the continued usage behavior for smartphone. The objective of this study is to explore how perceived usefulness, perceived enjoyment, and confirmation influencing satisfaction and habit of consumers, and in turn influencing continued usage behavior, as well as the moderating effect of three characteristics of m-commerce. The proposed model will empirically be tested using survey method and collecting data from smartphone users in longitudinal setting. The structural equation modeling technique will be used to evaluate the causal model and confirmatory factor analysis will be performed to examine the reliability and validity of the measurement model. The findings of this study are expected to illustrate how factors influence individuals to use m-services and mobile apps and become a habit, as well as how these habits influence continued smartphone usage
Plasmonic Circular Nanostructure for Enhanced Light Absorption in Organic Solar Cells
This study attempts to enhance broadband absorption in advanced plasmonic circular nanostructures (PCN). Experimental results indicate that the concentric circular metallic gratings can enhance broadband optical absorption, due to the structure geometry and the excitation of surface plasmon mode. The interaction between plasmonic enhancement and the absorption characteristics of the organic materials (P3HT:PCBM and PEDOT:PSS) are also examined. According to those results, the organic material's overall optical absorption can be significantly enhanced by up to ~51% over that of a planar device. Additionally, organic materials are enhanced to a maximum of 65% for PCN grating pitch = 800 nm. As a result of the PCN's enhancement in optical absorption, incorporation of the PCN into P3HT:PCBM-based organic solar cells (OSCs) significantly improved the performance of the solar cells: short-circuit current increased from 10.125 to 12.249 and power conversion efficiency from 3.2% to 4.99%. Furthermore, optimizing the OSCs architectures further improves the performance of the absorption and PCE enhancement
Img2Logo:Generating Golden Ratio Logos from Images
Logos are one of the most important graphic design forms that use an abstracted shape to clearly represent the spirit of a community. Among various styles of abstraction, a particular golden-ratio design is frequently employed by designers to create a concise and regular logo. In this context, designers utilize a set of circular arcs with golden ratios (i.e., all arcs are taken from circles whose radii form a geometric series based on the golden ratio) as the design elements to manually approximate a target shape. This error-prone process requires a large amount of time and effort, posing a significant challenge for design space exploration. In this work, we present a novel computational framework that can automatically generate golden ratio logo abstractions from an input image. Our framework is based on a set of carefully identified design principles and a constrained optimization formulation respecting these principles. We also propose a progressive approach that can efficiently solve the optimization problem, resulting in a sequence of abstractions that approximate the input at decreasing levels of detail. We evaluate our work by testing on images with different formats including real photos, clip arts, and line drawings. We also extensively validate the key components and compare our results with manual results by designers to demonstrate the effectiveness of our framework. Moreover, our framework can largely benefit design space exploration via easy specification of design parameters such as abstraction levels, golden circle sizes, etc
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