Food-deprived rats (Rattus norvegicus) will protect their food by dodging away from a conspecific. A detailed kinematic analysis of these movements in adult rats shows that each sex uses sex-typical movements. Females move their snout through a greater spatial curvature, and their snout achieves a greater velocity, relative to the pelvis, than males. Males make more hindpaw steps than females and achieve a more simultaneous movement of the fore- and hindquarters. This suggests that females pivot around a point more posterior on the body than males. The finding that functionally similar patterns of movement have a sex-specific organization provides a new dimension for the study of sex differences. These differences are discussed in relation to sex differences in sex-typical behaviors, associated body structure, and neural control. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Various assembly routines were evaluated under multitasking execution environment for a physical robotic cell. Analytical routines were determined by the SPT, LPT, and Branch and Bound algorithms for both cases of a single robot arm and two robot arms, and their performances in the physical simulation was observed. System efficiency and effectiveness were the major criteria evaluated to suggest the most desirable routines. 相似文献
We solve some problems related toray shooting in the plane, such as finding the first object hit by a query ray or counting the number of objects intersected by the query line. Our main results are an algorithm for finding the first hit when the objects are lines, and an algorithm for the case when the objects are segments. If the segments form simple polygons, this information can be used for reducing the complexity of the algorithms. The algorithms are efficient in space and in query time. Moreover, they are simple and therefore of practical use.This research was partially supported by the NY Metropolitan Research Fund. The second author is currently at IBM Haifa Research Group, Haifa 32000, Israel. 相似文献
Automated and computer-based systems for the dynamic management of complex engineering processes have been the subject of active research in recent years. Many of these systems have adopted methodology and technology from the field of artificial intelligence and expert system research.
In real-time process diagnosis and process management applications, where model based reasoning may be highly beneficial in terms of speed and functionality, a larger confluence of methods and approaches has started to form. The objective of these applications often includes, besides performing automated fault analysis and diagnosis, also establishing levels of confidence for the results that are obtained. Thus, both deterministic and uncertainty-based models and reasoning frameworks are often needed.
Of interest among the deterministic modeling techniques that can be used in a PMS (Process Management System) are binary trees, rule networks, and graph networks, which in turn include influence diagrams, logic flowgraph methodology and signed directed graph. PMS uncertainty management can be based on formal probabilistic methods, such as Bayesian estimation and updating, or less traditional methods such as certainty factors, Dempster—Schafer theory and fuzzy-set theory. The main features, advantages and disadvantages of the approaches and methods that are suitable for use in a PMS are critically examined and discussed. 相似文献
The 11-year longitudinal study of a right-handed male patient, L. C., who suffered from a severe amnesic syndrome following a softening in the right thalamus, is reported. Memory impairment involving retrograde and long-term anterograde memory, both verbal and spatial, persisted without modification. Investigation revealed some residual implicit learning ability. Positron emission tomography studies in the resting state displayed a bilateral hypometabolism of the mesial frontal lobes. Evidence suggests that a lesion confined to the thalamus may not on its own account for severe amnesia; that involvement of other structures is necessary for severe amnesia to appear; and that a functional investigation should always be included in cases of small thalamic lesions before drawing conclusions about the structures responsible for a given deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The low-temperature geothermal field of Nea Kessani, located in NE Greece, is characterized by a thermal reservoir made up of arkosic sandstones. The temperature distribution at depth, inferred from exploratory and productive wells, indicates that hot fluids rising from depth enter the arkosic reservoir in a restricted area of the field and flow towards local thermal springs. Well production tests have revealed the presence of hydrogeological boundaries within the arkosic reservoir.The geochemical characteristics of the thermal waters, which have an NaCl/HCO3 composition and salinity varying between 5 and 6 g/L, indicate that these waters undergo conductive cooling within the reservoir. No admixture of waters from the aquifers in the cover has been observed. The slight chemical differences existing between the thermal waters are probably caused by CO2, which represents about two thirds by volume of the discharged fluid. This CO2, as indicated by its isotopic composition, could originate from decomposition of marbles of the Paleozoic basement underlying the arkosic reservoir and may also affect the isotopic composition of the thermal waters, which exhibit an interesting positive oxygen shift. However, such a shift could also be the result of water-rock exchange processes at low temperatures, since the water feeding the field comes from a regional circulation which, as indicated by its deuterium content, has recharge areas on the Rhodope Chain. Alternatively, the shift could be attributed to the contribution of a deep-seated high-temperature geothermal reservoir, but a present there is no evidence of high-temperature resources in the region. A maximum temperature of 110°C has been estimated by quartz geothermometry.The physical, chemical and hydrogeological data available so far have permitted us to formulate a fluid circulation model for the Nea Kessani geothermal field. 相似文献
Two triangulation methods for measuring perceived egocentric distance were examined. In the triangulation-by-pointing procedure, the observer views a target at some distance and, with eyes closed, attempts to point continuously at the target while traversing a path that passes by it. In the triangulation-by-walking procedure, the observer views a target and, with eyes closed, traverses a path that is oblique to the target; on command from the experimenter, the observer turns and walks toward the target. Two experiments using pointing and 3 using walking showed that perceived distance, averaged over observers, was accurate out to 15 m under full cue conditions. For target distances between 15 and 25 m, the evidence indicates slight perceptual underestimation. Results also show that observers, on average, were accurate in imaginally updating the locations of previously viewed targets. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Recycling of spent filter backwash water is a widely practiced residual management approach throughout the United States for drinking water utilities. The United States Environmental Protection Agency (USEPA), under the 1996 Safe Drinking Water Act Amendments, has recently proposed regulations governing the recycle of this waste stream. Considering this new regulation, a comprehensive study was conducted by researchers at Colorado State University, and a suspended solids mass balance model was developed to characterize the impact of backwash water recycling on the overall treatment process. Online particle count data indicated that certain recycle practices could impact the overall treatment process. Data from pilot-scale experiments showed that total suspended solids (TSS) is a useful tool for characterizing the impacts of the backwash recycle processes. TSS can be used to assess whether solids loading or suboptimal coagulation conditions are the cause of recycle related issues. For the study described here, filter breakthrough occurred at about the same total influent solids load, regardless of the manner in which backwash recycling was performed, indicating that recycle of backwash solids did not impact the overall treatment process. 相似文献
Risk assessment methods vary in nature and depth. Their application to the evaluation of information security issues should be decided on the basis of their capability to provide answers to the fundamental questions concerning the design and implementation of security controls in specific information systems. Information systems risk analysis is discussed as a means of providing an objectively based approach for assessing and managing risk. As a decision making and risk assessment tool, rigorous risk analysis is not only capable of identifying potential losses that could be unacceptable for a given system, but it can be used to determine which specific security controls and counter measures can be effective and justifiable by management-set criteria.The Livermore Risk Analysis Methodology (LRAM) was developed in accord with these principles. Its model and procedures, from the identification of valuable assets to the prioritization and budgeting of proposed controls, are examined and discussed both from the technical and from the decision making/risk management perspectives. 相似文献