Computer Usage With Cold Hands; An Experiment With Pointing Devices Anna-Christina Blomkvist, Gunvor Gard, 429-450 Observation Procedures Characterizing Occupational Physical Activities: Critical Review Denys Denis, Monique Lortie, Michel Rossignol, 463-491 The Relationship Between Critical Flicker Fusion Frequency (CFFF) and Temperamental Characteristics Anna Łuczak, Andrzej Sobolewski, 493-505 Impact Resistance of Materials for Guards on Cutting Machine ToolsCRequirements in Future European Safety Standards Detlef Mewes, Rolf-Peter Trapp, 507-520 Dynamic Performance of Horizontal Flexible Anchor Lines During Fall ArrestCA Numerical Method of Simulation Krzysztof Baszczyński, Zygmunt Zrobek, 521-534 A Classification System for Characterization of Physical and Non-Physical Work Factors Ash Genaidy, Waldemar Karwowski, Paul Succop, Young-Guk Kwon, Ahmed Alhemoud, Dev Goyal, 535-555 Prevalence of Musculoskeletal Disorders at Workplaces in the People's Republic of China Stephen Bao, Jørgen Winkel, Houshang Shahnavaz, 557-574

Computer Usage With Cold Hands; An Experiment With Pointing Devices
Anna-Christina Blomkvist, Gunvor Gard

Computers are used in the outdoors and in connection with cold store work. Cold hand and fingers limit data input, as studied here. Six input devices; trackballs, pens, and a mouse were tested by 19 participants in a Fitts' target acquisition task with 2 target sizes under 2 experimental conditions; warm and cold right hand. Measures were acquisition times, number of errors, participant's preferences, and observed handling of the devices. Effects of device, target size, and cold were significant. Learning and attempts to improve handgrip were confirmed. Large enough targets, a thick pen, and a mouse make computer work practicable in the cold. Direct visual feedback, as with pen on template with target images, shortened acquisition times by half a second.

Observation Procedures Characterizing Occupational Physical Activities: Critical Review
Denys Denis, Monique Lortie, Michel Rossignol

The first objective of this paper is to compare the observation procedures proposed to characterize physical work. The second objective is to examine the following 3 methodological issues: reliability, observer training, and internal validity. Seventy-two papers were reviewed, 38 of which proposed a new or modified observation grid. The observation variables identified were broken down into 7 categories as follows: posture, exertion, load handled, work environment, use of feet, use of hands, and activities or tasks performed. The review revealed the variability of existing procedures. The examination of methodological issues showed that observation data can be reliable and can present an adequate internal validity. However, little information about the conditions necessary to achieve good reliability was available.

The Relationship Between Critical Flicker Fusion Frequency (CFFF) and Temperamental Characteristics
Anna Łuczak, Andrzej Sobolewski

The analysis in this paper was based on data obtained from 80 male participants, aged 29-65. Critical Flicker Fusion Frequency (CFFF) was measured using the Flicker Test. The Formal Characteristics of BehaviourCTemperament Inventory (FCB-TI) by Strelau and Zawadzki (1993) was used for temperamental characteristics. The results of statistical analysis did not confirm a hypothesis about the correlation between CFFF level and 3 temperamental characteristics. There were no immediate relationships among those variables. Correlation was observed when the CFFF coefficient of variance, instead of average CFFF values, was taken into account, especially in the case of a division into 2 groups of participants, "reckless" and "unsure." It could be interesting to check in the future a hypothesis about the stability of selected types of reactions.

Impact Resistance of Materials for Guards on Cutting Machine ToolsCRequirements in Future European Safety Standards
Detlef Mewes, Rolf-Peter Trapp

Guards on machine tools are meant to protect operators from injuries caused by tools, workpieces, and fragments hurled out of the machine's working zone. This article presents the impact resistance requirements, which guards according to European safety standards for machine tools must satisfy. Based upon these standards the impact resistance of different guard materials was determined using cylindrical steel projectiles. Polycarbonate proves to be a suitable material for vision panels because of its high energy absorption capacity. The impact resistance of 8-mm thick polycarbonate is roughly equal to that of a 3-mm thick steel sheet Fe P01. The limited ageing stability, however, makes it necessary to protect poycarbonate against cooling lubricants by means of additional panes on both sides.

Dynamic Performance of Horizontal Flexible Anchor Lines During Fall ArrestCA Numerical Method of Simulation
Krzysztof Baszczyński, Zygmunt Zrobek

Designing fall arrest systems, which contain horizontal flexible anchor lines is an important technical problem related to the safety of people who work at a height and need horizontal freedom of movement. The article presents a numerical simulation of the dynamic performance of horizontal flexible anchor lines during fall arrest. The model of a 2-component systemCa horizontal flexible anchor line and a falling rigid mass, described with a second order non-linear differential equationCis the main element of this method. This method of simulation is realised by a computer program, which allows obtaining the most important data characterising a fall arrest. The article shows laboratory tests used for the verification of this method, which turned out to be a valuable source of information and which can be used for designing fall arrest systems.

A Classification System for Characterization of Physical and Non-Physical Work Factors
Ash Genaidy, Waldemar Karwowski, Paul Succop, Young-Guk Kwon, Ahmed Alhemoud, Dev Goyal

A comprehensive evaluation of work-related perfomance factors is a prerequisite to developing integrated and long-term solutions to workplace performance improvement. This paper describes a work-factor classification system that categorizes the entire domain of workplace factors impacting performance. A questionnaire-based instrument was developed to implement this classification system in industry. Fifty jobs were evaluated in 4 different service and manufacturing companies using the proposed questionnaire-based instrument. The reliability coefficients obtained from the analyzed jobs were considered good (.589 to .862). In general, the physical work factors resulted in higher reliability coefficients (.847 to .862) than non-physical work factors (.589 to .768).

Prevalence of Musculoskeletal Disorders at Workplaces in the People's Republic of China
Stephen Bao, Jørgen Winkel, Houshang Shahnavaz

This paper presents 2 musculoskeletal disorders questionnaire surveys in 10 different Chinese occupational groups. Data collected from 1,603 workers using a modified Nordic musculoskeletal disorders symptom questionnaire showed that the 12-month prevalence of musculoskeletal disorders, particularly in the low back and shoulder-neck regions, was high at many Chinese workplaces. Significant differences existed between occupational groups. Assembly workers usually had higher neck-shoulder complaints compared to workers in most other occupations. However, the nature of assembly seemed also to influence the prevalence rate. Workers at a cassette recorder and a TV set assembly plant appeared to have more neck complaints compared with a group of thermos flask assemblers.