存在视场丢失的机器视觉精度补偿方法

无论Eye-in-Hand或Eye-to-Hand型式的机器视觉控制系统,均存在视场受限、丢失等情况,从而无法在一定距离、角度内对目标进行在线视觉测量,进而无法建立全闭环的伺服控制.基于Eye-in-Hand型式的机器视觉控制系统,以及最短测量距离L_min,提出一种闭环与开环相结合的伺服控制系统:即测量距离大于L_min时为位置反馈型闭环控制的原位调姿,在测量距离小于L_min时为位置给定型开环控制,机器人以相对线性运动进给到目标位置.针对该过程中的偏移问题,提出了前馈补偿模型,即利用前期运动数据对运动误差进行估计.实验证明,该方法能有效地补偿定位误差.     

Psychosocial problems of the aged: a shared medical responsibility

The respective roles of the psychiatrist and the family physician in dealing with the psychologic and some of the social problems of the aged are briefly outlined. By close cooperation of these two groups of physicians, many aged patients can be helped. More important is the fact that both groups of physicians can contribute to a change in attitude toward aging among the younger members of society. This offers hope that many of the psychosocial problems of the aged can be minimized or prevented.     

Residual vision with awareness in the field contralateral to a partial or complete functional hemispherectomy

Two patients with unilateral disconnection or removal of the entire occipital lobe were tested for residual vision in their blind field. Using image stabilization to eliminate eye motion artifacts, the central portion of each subject's visual field was tested, beginning 1 degree from fixation and extending outward to 13.5 degrees. A narrow zone of residual vision was identified along the retinal vertical meridian of each patient. The lateral edge of this zone was generally within 3.5 degrees of the vertical meridian, though extended farther outward (but not beyond 6 degrees) at one field location for each subject. In one patient, it was present in both superior and inferior quadrants; in the other, it was confined to the superior quadrant. Within their zones of residual vision, both patients could detect stimuli and perform simple shape discriminations, but could not name complex line drawings. The patients were aware of their vision within this zone. No residual vision, with or without awareness, was found in areas tested outside these zones. Given the complete absence of visual cortex contralateral to the observed residual vision, alternate structures must be mediating these abilities.     

Epi-macular holes: a cause of decreased vision in the elderly

The development of epi-macular holes in the elderly represent a maculopathy which resembles senile macular hole and surface wrinkling retinopathy. Clinically it is most likely a sub-type of surface wrinkling retinopathy in which a hole forms in the epi-macular membranes. The findings in 11 patients with this condition are described.     

Keeping an eye on vision: primary care of age-related ocular disease. Part 1

Normal changes in the lens, retina, and vitreous accompany aging, but loss of vision in late life is not an inevitable consequence of aging. Cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration (ARMD) account for most vision loss in the older population. Visual impairment reduces older patients' ability to function independently and increases their risk of depression and of injury due to falls. When older persons have a visual complaint, they tend to blame it on being old and do not tell their physicians. In the primary care office, simple screening questions and examination of the dilated eye can often reveal a need for further examination and/or referral.     

Reversible modification of the Goldmann perimeter for the assessment of the field of binocular single vision

Sixty eight Neisseria gonorrhoeae strains were isolated from endocervical and urethral discharge of 233 patients attending health centres for sexually transmitted diseases (STDs) in Addis Ababa, were identified following conventional procedures and tested for susceptibility to penicillin, ampicillin, trimethoprim-sulphamethoxazole (bactrim), chloramphenicol, erythromycin and kanamycin by the agar disc diffusion technique. Penicillinase producing N. gonorrhoeae (PPNG) were identified using the chromogenic cephalosporin method and comprised 70% of the isolates. Seventy seven per cent, 73%, 64% and 17% of the isolates were found to be resistant to penicillin, ampicillin, bactrim and kanamycin, respectively. However, no resistance to erythromycin and chloramphenicol was observed. Multiple drug resistance was found to be 67%. This is a cause for concern in the control and treatment of gonococci.     

Differential diagnosis of decreased vision: a case study

Three patients who suffered transitory (from 18 to 49 days) cranial dyskinesias during the course of tubercular meningitis are described. The diagnosis was confirmed by the presence of acid-alcohol resistant bacilli in spinal fluid. Cranial tomography or magnetic resonance images failed to demonstrate anatomical lesions. The blink reflex and brain stem auditory evoked potentials were abnormal, indicating dysfunction of motor nuclei of the cranial nerves, possibly secondary to changes in their regulation by basal ganglia. No recurrences have been observed during follow-up (from 3 to 7 years).     

Excessive responsibility in obsessional concerns: a fine-grained experimental analysis

OBJECTIVE: To assess the relation between ventricular arrhythmias after myocardial infarction and left ventricular remodelling. DESIGN: Prospective study with consecutive patients. METHODS: 97 patients with acute myocardial infarction underwent serial echocardiographic examinations (days 1, 2, 3, and 7, and after 3 weeks) to determine end diastolic volume, end systolic volume, and ejection fraction; volumes were normalised for body surface area and expressed as indices. Holter monitoring was performed on the day of the final echocardiogram. Coronary angiography was performed in 88 patients before hospital discharge. RESULTS: Complex ventricular arrhythmias (defined as Lown class 3-5) were found in 16 of 97 patients. In logistic regression models, variables predictive of complex ventricular arrhythmias were end systolic volume index on admission (b = 0.054, P = 0.015) and end diastolic volume index after three weeks (b = 0.034, P = 0.012). Complex arrhythmias were also related to the increase of end diastolic and end systolic volume indices throughout the study (F = 5.62, P = 0.046, and F = 6.42, P = 0.017, respectively by MANOVA). A two stage linear regression model of ventricular volume versus time from infarct showed that both intercept (initial volume) and slope (rate of increase) were higher for patients with complex arrhythmias in both diastole and systole (P < 0.001 for all). CONCLUSIONS: Complex ventricular arrhythmias after myocardial infarction are related to the increase of left ventricular volume rather than to depressed ejection fraction. Complex arrhythmias may be an aetiological factor linking left ventricular remodelling with higher mortality, but larger follow up studies of patients with progressive left ventricular dilatation after myocardial infarction are necessary to answer these questions.     

Serving the underserved: Our societal responsibility.

Discusses pending Congressional actions regarding a federal role in health care and the responsibility of mental health care professionals in shaping policy aimed at ensuring the maintenance of mental health care service provision. The challenge of the Substance Abuse and Mental Health Services Administration (SAMHSA) is to convince policymakers that existing and newly designed programs are meaningful and are accountable for significant results in terms of improved services, greater efficiency, and successful measurable outcomes. The programs of 3 SAMHSA centers, the Center for Mental Health Services, the Center for Substance Abuse Prevention, and the Center for Substance Abuse Treatment, focussing on these issues are delineated. Issues in the advancement of Telehealth-Telemedicine and mental health care components of treatment for the elderly in long-term care facilities are also described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motion parallax: effects of blur, contrast, and field size in normal and low vision

Can people with different forms of low vision use motion parallax to improve depth judgments? We used a staircase method to compare depth thresholds using motion parallax and static viewing. We tested eighteen normal-vision subjects with a range of simulated deficits in acuity, contrast sensitivity, and simulated peripheral-field loss, and ten low-vision subjects with a wide range of acuity, contrast sensitivity, and field loss. Subjects viewed three vertical cylinders monocularly and indicated which one was at a different depth from the other two. For motion-parallax trials, observers moved their heads (in a viewing assembly on rollers) from side to side over a range of 6-12 cm. For static trials, the viewing assembly was fixed in place. Normal-vision subjects' depth thresholds with motion parallax were significantly smaller than those with static viewing by an average factor of 1.95 (p < 0.05) across all levels of acuity and contrast. For low-vision observers, the depth thresholds exhibited large individual differences; however, the motion-parallax thresholds were smaller than the static thresholds by an average factor of 2.05 (p < 0.01). These findings indicate that motion parallax can provide useful depth information for people with low vision.     

Negotiation of responsibility: Judgments of blameworthiness in a natural setting.

Conducted naturalistic observations over a 5-day period of remedial interchanges—situations in which a participant is called on to defend his/her behavior or character—occurring among approximately 300 students in 10 different classrooms representing kindergarten through 3rd-grade levels. Data yielded 1,718 remedial interchanges, which were broken down by grade and presence or absence of a teacher. Three approaches to the development of moral judgments were considered: attributional, cognitive-developmental, and symbolic-interactionist analyses. Data show limited support for the model of levels of responsibility (attributional analysis) developed by F. Heider (1958), no evidence of an objective–subjective shift, and no evidence for either Piaget's (1965) or L. Kohlberg's (1969) notions of the importance of reciprocity norms to judgments of blame (cognitive-developmental analysis). The use of intent in Ss' discussions of responsibility was rare, did not change with age, and occurred most often in response to accusation of physical damage to a person or property. Results are compatible with the symbolic-interactionist notion that the assignment of responsibility is a matter of negotiation among interactants to establish a shared meaning or definition of the situation. Findings suggest that children have context-specific criteria for blame judgments. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partnership in nursing education: a vision or a fantasy?

Reliability of Energetic Meridian Measurement with Prognos A(R) OBJECTIVE: Is energetic measurement of the Traditional Chinese medicine (TCM) meridians with Prognos A a reliable method? PATIENTS: 30 healthy volunteers from the staff of the Stauferklinik, Schw? bisch Gmü nd, Germany. DESIGN: Measuremeuts are taken 4 times from each person at all terminal locations of the meridians (24 points) on fingers and toes with Prognos A. Breaks between each measurement run lastet 2-5 min. The values of skin resistance are compared. RESULTS: Reliabilities of the single meridian measurements range between 0.44 and 0.82 with an overall reliability of 0.72. Lowest reliability is seen in yang -hollow organs, probably a due to their intense lability. Mediating of 4 single runs shows a reliability of 0.9. CONCLUSIONS: Our measurement of reliability confirms Prognos A as a reliable device of determinating skin resistance, especially with repeated measurements. Variations of the readings are probably due to the special quality of the meridian system; increased variations of special meridians seem to be explainable by their characteristic features defined in TCM.     

Attributions of responsibility for helping and doing harm: Evidence for confusion of responsibility.

The social inhibition of helping has been explained in terms of the general processes of audience inhibition, social influence, and diffusion of responsibility. The present research adapted the paradigm used in studies of the attribution of responsibility for an accident to examine a specific audience-inhibition process that may contribute to the social inhibition of helping. Evidence from 2 experiments, with 356 undergraduates, shows that an S who adopted the perspective of a helper following an accident expected to be held increasingly responsible by arriving onlookers for the victim's plight as the number of extant bystanders increased. Results also indicate that there was an objective basis for this expectation: Ss who adopted the perspective of a newly arriving onlooker increasingly attributed responsibility for doing harm to the individual helping the victim in the accident as the number of bystanders described as already at the scene increased. The distinction between confusion and diffusion of responsibility is emphasized, and limitations to confusion of responsibility for accidents are discussed. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geriatric care: where does the responsibility lie?

In contrast to purposeful efforts in South Africa to lay sound foundations for the development of social services for the aged, little constructive planning has been done by medical authorities to provide for the special health needs of the elderly on a national basis and based on recognised geriatric principles.     

Active noise control: a review of the field

Active noise control (ANC) is the application of the principle of the superposition of waves to noise attenuation problems. Much progress has been made toward applying ANC to narrow-band, low-frequency noise in confined spaces. During this same period, the application of ANC to broad-band noise or noise in three-dimensional spaces has seen little progress because of the recent quantification of serious physical limitations, most importantly, noncausality, stability, spatial mismatch, and the infinite gain controller requirement. ANC employs superposition to induce destructive interference to affect the attenuation of noise. ANC was believed to utilize the mechanism of phase cancellation to achieve the desired attenuation. However, current literature points to other mechanisms that may be operating in ANC. Categories of ANC are one-dimensional field and duct noise, enclosed spaces and interior noise, noise in three-dimensional spaces, and personal hearing protection. Development of active noise control stems from potential advantages in cost, size, and effectiveness. There are two approaches to ANC. In the first, the original sound is processed and injected back into the sound field in antiphase. The second approach is to synthesize a cancelling waveform. ANC of turbulent flow in pipes and ducts is the largest area in the field. Much work into the actual mechanism involved and the causal versus noncausal aspects of system controllers has been done. Fan and propeller noise can be divided into two categories: noise generated directly as the blade passing tones and noise generated as a result of blade tip turbulence inducing vibration in structures. Three-dimensional spaces present a noise environment where physical limitations are magnified and the infinite gain controller requirement is confronted. Personal hearing protection has been shown to be best suited to the control of periodic, low-frequency noise.