Network Formation in the Political Blogosphere: An Application of Agent Based Simulation and e-Research Tools

The political blogosphere has become the focus of attention of researchers from disciplines such as political science and network science. In a recent paper, Adamic and Glance (LinkKDD ’05: Proceedings of the 3rd international workshop on link discovery, 2005, pp. 443–452) report differences between the linking behavior of politically conservative versus politically liberal web bloggers. We construct a simple agent-based network formation model which shows that one such difference, demonstrating what we term ‘political homophily’, can be generated by connecting the blogosphere to the underlying population distribution of political preferences. The model is implemented as a web service in the e-Research tool VOSON (Virtual Observatory for the Study of Online Networks), and both model and tool serve to define a natural environment for research into link formation behavior with large numbers of heterogeneous network participants.     

Studies of cache store behaviour in a real-time minicomputer environment

The letter reports simulation studies of cache storage in a real-time minicomputer environment. Direct mapping is shown to be the most effective approach to cache management and the speedup achieved is also seen to depend on the class of program. Speedup factors of more than 5:1 can be achieved with modest-sized cache stores and relatively simple hardware.     

CMOS在视频摄像器上的应用

比较了ＣＭＯＳ和ＣＣＤ技术在视频摄器领域中应用情况,重点描述了一种ＣＭＯＳ传感器的设计和制作。这种传感器的特点是在同一个芯片个集中大量的计算元件,形成传感器阵列,这样保证 探测的图像信息能够以直接满足多本计算机要求的形式输出。     

Future trends in the use of X-ray fluoroscopy for the measurement and modelling of joint motion

Knowledge of three-dimensional skeletal kinematics during functional activities such as walking, is required for accurate modelling of joint motion and loading, and is important in identifying the effects of injury and disease. For example, accurate measurement of joint kinematics is essential in understanding the pathogenesis of osteoarthritis and its symptoms and for developing strategies to alleviate joint pain. Bi-plane X-ray fluoroscopy has the capacity to accurately and non-invasively measure human joint motion in vivo. Joint kinematics obtained using bi-plane X-ray fluoroscopy will aid in the development of more complex musculoskeletal models, which may be used to assess joint function and disease and plan surgical interventions and post-operative rehabilitation strategies. At present, however, commercial C-arm systems constrain the motion of the subject within the imaging field of view, thus precluding recording of motions such as overground gait. These fluoroscopy systems also operate at low frame rates and therefore cannot accurately capture high-speed joint motion during tasks such as running and throwing. In the future, bi-plane fluoroscopy systems may include computer-controlled tracking for the measurement of joint kinematics over entire cycles of overground gait without constraining motion of the subject. High-speed cameras will facilitate measurement of high-impulse joint motions, and computationally efficient pose-estimation software may provide a fast and fully automated process for quantification of natural joint motion.     

Accuracy of injury coding in Victorian hospital morbidity data

In Victoria injury surveillance data are drawn from hospital morbidity data. The accuracy and reliability of these data are often questioned. We aimed to ascertain the reliability of injury data in the Victorian inpatient minimum database. A random sample of 546 public hospital separations with principal diagnosis ICD-9-CM codes 800-999 was selected from four metropolitan hospitals. Medical records were reviewed, and the hospital coding was compared with the record content. The frequency of error in any coding field was 73 per cent (349/480); of diagnosis error, 61 per cent (292/480); of procedure error, 45 per cent (168/370); of error in the principal diagnosis, 19 per cent (93/480); and of error in external-cause codes (E-codes), 16 per cent (75/480). Ninety-four per cent of errors (87/93) in the principal diagnosis involved recoding within the same group of codes. Only 6 per cent (6/93) were recoded to principal diagnoses other than injury. Sixty-two per cent (181/292) were errors of omission of codes for comorbid conditions. Nearly half the errors in the principal diagnosis were minor, involving the last two digits. E-codes were more complete than diagnosis codes. The best predictors of error in the principal diagnosis were greater length of stay, type of injury code (poisonings and toxic effects were associated with lower error rates) and death as the outcome. While selection of data from secondary diagnosis fields may not provide complete data, the use of the principal-diagnosis code and E-codes for injury surveillance is feasible and reliable. The database is a valuable source of injury surveillance data, bearing in mind the limitations of coded hospital morbidity data.