This study aims to investigate laws and standards(including technical guidelines) related to safety criteria for 22 kitchen machines frequently used in commercial kitchens. The study was based on literature survey, interviews with charge persons in kitchen machines manufacturing companies, cafeteria providing group meals and relevant association, and web surfing. The results showed that there are two types of safety criteria such as legally forced ones by laws and optional ones by national industrial standards or technical guidelines. High pressure safety control act, safety control and business of liquefied petroleum gas act and city gas business act prescribed gas use apparatus safety criteria, rational energy utilization act did those of pressure vessel such large rotary caldron, industrial health and safety act did those of food processing machinery, and electrical appliances safety control act did those of electrical kitchen appliances. Compulsory or optional standards or guidelines related to safety criteria for kitchen machines were presented by 22 kitchen machines. Safety devices shown in the laws, standards and guidelines were also summarized by kitchen machines and their risk factors.

The purpose of this study is to investigate EU, UK and USA’s laws and standards related to safety criteria for commercial kitchen machines. The study was based on literature survey and web surfing. The results revealed that EU has relevant directives by kitchen machines and harmonized standards according to the directives. The directives and harmonized standards are translated into the laws and standards of EU member countries, respectively. The kitchen facility relevant legal systems of UK and USA do not prescribe the safety devices or measures, but only the basic health and safety requirements. The requirements were forcefully implemented through the certificate systems such as CE(Confommite European), UL(Underwriters Laboratories), etc. Only products with CE, UL or NRTL(ationally Recognized Testing Laboratory) certificate marking can be placed on the market of EU and USA, or put into service. For achieving the certificates, all requirements regulated in the relevant standards should be met. The standards of UK and USA were presented by kitchen machines or by standards themselves, respectively. Safety devices required by the standards were also summarized by kitchen machines and their risk factors.

This study tried to investigate the difference of the legibility in different age groups (young and old) with same near visual acuity and to provide preliminary guidelines for the text sizes in the pesticides products based on the legibility experiments. To achieve the objective, legibility evaluation experiments were conducted to test the effects of different age(20s, 50-60s), gender, font type(thick gothic-type and fine gothic-type), thickness (plain and bold), and number of syllables(2 and 3 syllables) in the same near visual acuity(0.6). The results showed that legibility 50s was higher than 20s. And 20s are appealed higher discomfort than 50s. Considering these experimental results, it was recommended that the 14 pt or larger characters (100% readable size) should be used the important information such as toxicity, and the minimum character size was 7 pt (50% readable size) for other information.

Manual materials handling tasks are the main risk factors for the work-related musculoskeletal disorders. Many assistant tools for manual materials handling are being used in various kind of industries. One of them is a 4-wheeled cart which is widely used in manufacturing factories, hospitals, etc. The major force required to control the 4-wheeled cart is pushing and pulling. There are two types of handles being used for the 4-wheeled cart : vertical type (two vertical handles), and horizontal type (one horizontal handle). This study tried to investigate the pushing forces and subjective discomforts (hand/writst, shoulder, low back, and overall) of the two handle types with different handle height and distance conditions. Twelve healthy male students (mean age = 23.4 years) participated in the experiment. The independent variables were handle angle (horizontal, vertical), handle height (low, medium, high), and handle distance (narrow, medium, wide). The full factorial design was used for the experiment and the maximum pushing forces were measured in 18 different conditions (2×3×3). Analysis of variance (ANOVA) procedure was conducted to test the effects of the independent variables on the pushing force and discomfort levels. Handle height and angle were found to be the critical design factors that affect the maximal pushing forces and subjective discomfort. In the middle height, subjects exerted higher pushing forces, and experience lower discomfort levels compared to the high, and low height. There was no statistical influence of the handle distance to the pushing forces and subjective discomfort levels. It was found out that the effects of the handle angle (horizontal and vertical) on both pushing force and subjective discomfort were statistically significant (p < 0.05). The vertical handle revealed higher pushing force and lower discomfort level than the horizontal handle. The reason for that was thought to be the different postures of the hand when grasping the handles. The horizontal handle induced pronaton of the hand and made hand posture more deviated from the neutral position.

Among various manual materials handling tasks, pushing/pulling was known to be one of the risk factors for the low back and shoulder musculoskeletal disorders (MSDs). This study was conducted to find out an optimal solution set of the handle height and distance for 4-wheel cart with two vertical handles. Ten male college students participated in the pushing force measurement experiment. The face-centered cube design, one of the central composite designs, was applied for the experiment, and the isometric voluntary pushing force was measured in 9 treatment conditions. The second order response surface model was predicted by using the pushing strength as a response variable, and the handle height and distance as independent factors. According to the 2nd order response model, the handle height and distance showed nonlinear relationship with the isometric pushing strength. To maximize the 2nd order response model (pushing force), the handle height and distance were optimized. The optimal handle height was 'xyphoid process height - stature’, and the optimal handle distance was ‘1.25*shoulder width’. When calculated using the anthropometric data of the subjects of this study, the optimal handle height was 115.4 ± 3.4 cm, slightly higher than the elbow height, and the handle distance was 52.9 ± 2.3 cm.

Safety and health related information for the proper use and handling of pesticides is usually printed on the surface of the pesticide products (bottle type or bag type) in the form of texts. But, the guidelines or standards for the appropriate presentation of the texts for the pesticide products are most vague or not practical. Thus, this study aimed to provide the preliminary guidelines for the text sizes based on the legibility experiments. Total twenty subjects from two age groups (young: n=10, old: n=10, five males and five females in each group) participated in the experiment. First, subjects read the text cards presented in the distance of 50cm from the eyes of the subjects. Eight different text card sets were prepared for different font type(thick gothic-type and fine gothic-type), thickness of font(plain and bold), and number of syllables (2 and 3 syllables). When subjects read the cards, the correctness of reading (correct or wrong) was recorded and the degree of discomfort (from 1: no discomfort at all to 4: can't read at all) was also evaluated for all the text sizes. Results showed that the character size should be 4 pt or larger for the young subjects to read at least one word correctly in all the text conditions. For the old subjects to read at least one word correctly, the character size should be five pt or larder. The average of the minimum character sizes for 100% correct answer is 6.1 pt for young subjects and 10.5 pt for old subjects, respectively.

The mask-face interface design should consider the face shape to improve the half mask respirator's fit ratio. This study tried to design the mask-face interface using recent Korean face data. By using the data of 1536 men's 3D face scanning (Size Korea data), head clay mock-up was made and mask-face interface line was extracted from this head mock-up. Using this interface line, the half-mask prototype was made. According to the quantitative fitting test, the proposed mask was found to be well fitted (average fit-ratio > 100). The proposed method had two advantages. 1) The method could use massive head-related anthropometric data like Size Korea data. 2) The qualitative fit test (observation) could be conducted very quickly by fitting the prototype to the head mock-up. However, this method also had several limitations. 1) The head clay mock-up could be different according to the mock-up maker. 2) The average values of the head-related anthropometric data were used to make the head mock-up. Small and large size head mock-ups should be made and tested.

Texts and icons are used to deliver the safety and health information on pesticide labels. This study surveyed the standards or guidelines regarding the presentation formats of texts and icons used in pesticides. Also, the text and icon formats being used in the 50 pesticide products in Korea were investigated in the aspects of size, font (texts only), color. From the guideline survey, it was found that while the guidelines for the text fonts and colors in pesticides were suggested, there was no detailed guidelines about the text size. For the icon presentation, it was regulated that the icon size for the pesticides should be larger than 7mm×7mm, and this size was equivalent to the size when the reading distance of 28 ㎝ was applied to other two guidelines. From the sample survey of the 50 pesticides, it was found that the small text size being used in the 50 pesticides was 1mm (3pt), and this size was considered to be very difficult to be read, particularly by old people. The minimum size of the texts for the toxicity of the pesticide, the very important safety information, was found to be 1.5 mm, which is considered to be very uncomfortable to be read. The size of icons were varied from 2 to 12 mm, and the total average size was 4.6 mm. The 149 icons from a total 187 icons (80%) were smaller than the icon presentation guideline (7mm×7mm), and the reason for the small icon size might be the small area of the label of the pesticides. Thus, more detailed guidelines for the text size and more practical guidelines for the size of icons are required.

This study surveyed the reading discomforts and the reasons for discomfortable reading of the safety and health information (texts and icons) presented on the agricultural vehicles/machines, pesticides, fertilizers, and feeds. Eighty seven people residing in rural area participated in the survey interview. Questionnaire survey showed that the most discomfortable product in reading the texts was pesticides. Forty three (49%) among participants had very-discomfortable or discomfortable in reading the texts used in the label of pesticides, and the main reason for the discomfort was small text size. The reading discomforts in reading the texts (varied from 4 point to 19 point and presented in 50 cm reading distance) showed different pattern according to the age groups. Three age groups (50s, 60s and older than 70s) showed a similar discomfort pattern, but different from the group of 30s and 40s. Forty four people (51%) had a problem in understanding the meaning of the icons and the main reasons were the small size and the difficulty in inferring the meaning of the icons. Thus, the more detailed and practical guidelines for the presentation format, particularly about the text heights and the size of icons, are required. Also, more comprehensive research is needed to investigate the readability and legibility of texts and icons.

In this study, the effects of psychosocial stress (box color and precision demand) on muscle activity were evaluated in laboratory setting. Eight subjects performed sagittally symmetric lifting tasks. Box color (yellow, black), precision demand (yes, no), and box weight (5%MVC, 10%MVC, 15 %MVC) were varied and surface EMG signals from seven muscles(medial deltoid right, biceps brachii right, lateral triceps right, latissimus dorsi right, erector spinae right, external oblique right, internal oblique right) were recorded. EMG signals were band-pass filtered(10~400 Hz), rectified, RMS smoothed and normalized (NEMG). Analysis of variance tests were conducted on the total NEMG (TNEMG: the sum of the seven muscles' NEMGs) and on the individual muscle's NEMGs. Box color had no effect on the TNEMG and on the seven muscles activities(p〉0.05). When precision demand was required at the end point of lifts, the mean NEMG showed higher values than no precision demand conditions: TNEMG (14% increase) and medial deltoid(40% increase), biceps brachii(10% increase), lateral triceps(26% increase), latissimus dorsi(25% increase) muscles. Those increases showed more conspicuous as the box weight increased in the muscles of medial deltoid, lateral triceps, and latissimus dorsi.

There are many display panels in the flight cockpit and pilots get various flight information from those displays. The ergonomic layout of the displays must be determined based upon frequency of use and sequence of use. This study investigated the visual search patterns of the six display groups(one head-up-display: HUD, two multi function displays: MFDs, one engine group: EG, one flight display group: FD and others) in a fighting aircraft. Four expert pilots conducted Imaginary flight in the physical mock-up and the eye movements were collected using eye tracking system. Data of dwell time, frequency of use, and eye movement path were collected. Pilots spent most of time on HUD(55.2%), and others (21.6%), FD(14.2%), right MFD(4.7%), EG(3.2%), and left MFD(1.1%) in descending order. Similarly HUD(42.8%) and others(30.0%) were the most frequently visited displays. These data can be used in the layout of cockpit displays and the determination of optimal visual search pattern.

Indoor air quality tends to be the dominant contributor to personal exposure, because most people spend over 80% of their time indoors. In this study, indoor and outdoor NO2 concentrations were measured simultaneously with personal exposures of 30 university students in weekday and weekend in Daegu, Korea. House characteristics and subject's activity pattern were used to determine the effects on personal exposure. Since university students spent most of their times indoor, their NO2 exposure was associated with indoor NO2 level during both weekday and weekend in spite of different time activity. Using a time-weighted average model, NO2 exposures of university students were estimated by NO2 measurements in indoor home, indoor school, and outdoor home. In conclusion, major personal exposure to NO2 resulted from air quality of indoor environment at house.