• Journal of the Ergonomics Society of Korea
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• v.36 no.2
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• pp.145-156
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• 2017

Objective: This study aims to compare the usability of the adaptive touch design method with that of the height adjustable design method that are applied to the Korean QWERTY keyboard and Naratgul keyboard on smartphones, examine the results, and present practical implications. Background: Smartphone manufacturers have failed to satisfy every user with their uniform touch keyboard designs that do not consider the high use rates of keypad use. In reality, touch keyboard designing customized for every individual is impossible, but there need to be researches on was to improve usability by having touch areas changed automatically depending on user behaviors or having users adjust the keyboard height depending on their hand size. Method: As for the design methods, an object group was given smartphones with the adaptive touch design method and the other group those with the height adjustable design method. As they entered the same characters in the smartphones, typing error rates and text input speed were measured and the average values were compared. 35 individuals who would frequently use smartphones in daily life participated in the experiment. The group variable was the type of touch keyboards, and the test variables were typing error rates and text input speed, for which a T-test was implemented. Results: As for the QWERTY keyboard, the significant improvement effect was verified as the typing error rate of the adaptive touch design method was 4.21% but that of the height adjustable design method was 3.28% although there was no significant difference in terms of text input speed. As for the Naratgul keyboard, in contrast, the typing error rate of the adaptive touch design method was 2.5% while that of the height adjustable design method was 1.48%, which indicates a measure of improvement, but the effect was not significant. On the other hand, the text input speed per minute was improved as much as 22.2%, which is significant. Conclusion: First, the Korean touch keyboard usability of the adaptive touch design method and that of the height adjustable design method, when applied to Model A of Company L, showed significant difference from each other. Second, the height adjustable design method was applied to the QWERTY keyboard, the typing error rate was improved significantly. This indicates that as the keyboard height was raised, the number of buttons within the range of fingering decreased, decreasing the touch bias was reduced. Third, the height adjustable design method was applied to the Naratgul keyboard, the text input speed was improved. Application: When the QWERTY keyboard was applied to a smartphone as small as 5.5inch or less, it is highly probably that the height adjustable design method decreases the typing error rate. It may be considered to develop additional UX functions to make the keyboard font larger or give users the option to adjust button intervals in utilization of the SW advantages of the height adjustable design method.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.349-354
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• 2017

In this study, we proposed a design guideline of height-adjustable wash basin which is an assistive product for personal hygiene for persons with disability. We performed biomechanical assessments using both of conventional and prototype height adjustable wash basin. Total five elderly subjects (all male, age $68.6{\pm}4.3yrs.$, height $169.8{\pm}5.7cm$, weight $70{\pm}7.7kg$) participated for the assessment test. Each joint angles were measured by using a 3D motion capture system when subjects use wash basins, and the lumbar moment of each subjects was estimated based on a human body model. From the assessment results, a design guideline which has the range of the height from 652[mm] to 1162[mm] was proposed. Then additional assessment tests with five healthy subjects ($25.8{\pm}1.8yrs.$, $175.5{\pm}5.8cm$, $74{\pm}15.7kg$) were performed in order to verify effectiveness of the design guideline. The results showed a height-adjustable wash basin applied the proposed design guideline was effective to reduce the lumbar moment.

• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.125-137
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• 2009

Recently, the frequency in use of electric adjustable bed is going up by an increase in the elderly population. In bad ergonomic design for an electric adjustable bed causes some problems in the aspects of usability and safety. In particular, lots of accidents came from going up or going down an electric adjustable bed. In that case, the height of bed is very important factor for preventing an accident. This problem is related to its anthropometric factors. Therefore we carried out its anthropometric analysis and old people's standing action according the height of electric adjustable bed as an experimental study. As a result, we proposed some anthropometric design criteria and identified the effect of bed height when old people use it.

• Journal of Drive and Control
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• v.18 no.4
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• pp.19-27
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• 2021

A bunker bed is a type of furniture that efficiently utilizes a narrow indoor space by having a high bed and using the empty space below as a living and storage space. The demand for multi-purpose furniture is increasing due to the recent increase in single-person households and wide-spread shared accommodation. According to the consumer research, one of the major drawbacks of a bunker bed was to get on and off the bed through a ladder or stairs. In order to overcome these problems, it was confirmed that the height adjustment function that can easily adjust the minimum and maximum heights of the bed was necessary. In this study, a height adjustable bunker bed was designed by using a gas spring that generates a repulsive force by the compressed gas inside. The design process consisted of the following three steps: Firstly, the hysteresis characteristics due to a friction and spring constant of a commercial gas spring were confirmed by measuring the repulsive force vs. compressed displacement. Secondly, requirements of the vertical lifting force exerted on the bed against gravity force were derived. Finally, the height-adjustable bed using the four-bar link mechanism was designed with 4 parameters so that the bed weight of 60-70 kgf could be adjusted to 800 mm in height by an affordable initial operation force. The performance was verified through prototype production and the results of vertical displacement and force to move were nearly the same as designed. In addition, an electrically operated height-adjustable bed was also designed with linear actuators and the performance was proved with the prototype.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.515-518
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• 1997

Resident time of the centrifugal extractor for organic phase extraction using a height controlled separator weir and a divert plate is the important factor that affects significantly the chemical material extraction and the productivity in the chemical and mechanical processes. In this paper, it describes the design of the device for extraction of an organic phase from radioactive wastes, and considers phase separating weir and divert disk, both being designed to be adjustable in their positions, for effectively separating an organic phase. A height-adjustable separating weir unit used for separating the organic phase from the aqueous phase using a phase separating weir and designed to control the height of the separating weir as desired so as to allow the weir to be positioned at a boundary layer between two separated phases. The centrifugal extractor controls satisfactorily the mixed reaction time of two phases within the separator regardless of the variations of the mixing ratio of the two phases and the rotating speed of the extractor, is designed to be adjustable in its position in the vertical direction, thus allowing the user to appropriately select the mixed reaction time of the two phases within the extractor as desired. From development of a centrifugal extractor, it can effectively recover such usable elements, and preferably reducing the output quantity of radioactive wastes.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.3
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• pp.207-214
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• 2016

Optical communication systems are rapidly spread following increases in data traffic. In this work, a 32-Gb/s inductorless output buffer circuit with adjustable pre-emphasis is proposed. The proposed circuit consists of an output buffer circuit and an emphasis circuit. The emphasis circuit emphasizes the high frequency components and adds the characteristics of the output buffer circuit. We proposed a design method using a small-signal equivalent-circuit model and designed the compensation characteristics with a 65-nm CMOS process in detail using HSPICE simulation. We also realized adjustable emphasis characteristics by controlling the voltage. To confirm the advantages of the proposed circuit and the design method, we fabricated an output buffer IC with adjustable pre-emphasis. We measured the jitter and eye height with a 32-Gb/s input using the IC. Measurement results of double-emphasis showed that the jitter was 14% lower, and the eye height was 59% larger than single-emphasis, indicating that our proposed configuration can be applied to the design of an output buffer circuit for higher operation speed.

• Journal of the Ergonomics Society of Korea
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• v.20 no.1
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• pp.15-29
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• 2001

This study was conducted to develop a prototype of adjustable desk and chair for students from elementary to high school. The development process started with identifying the problems of existing adjustable desks and chairs that are currently available in the market. The following fundamental design criteria were established and then applied to develop the prototype. The criterion of minimization of production cost yielding lower the market selling price was the most critically considered in view of the school furniture buyers' price-consciousness. Other design criteria used in this development were designing for stable and solid structure, requiring few motions and no tools to adjust, requiring the use of only one hand to adjust, unrestricting the adjustable interval, providing extra space for foot and knee area, reducing weight to move easily, and requiring not to move around for cleaning up floor. To evaluate the performance of the prototype, the adjustability of prototype was specifically compared with both dimensions suggested by KS G 2010(Korean Standards for desks and chairs for students) and current anthropometric dimension in terms of the flexible range of accommodation. Results of this study illustrate that the prototype developed in this study could be accommodated for the both dimensions. As a concluding mark, appropriate adjustable range for various grades and age groups were presented.

• The Journal of the Convergence on Culture Technology
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• v.4 no.1
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• pp.331-335
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• 2018

A pillow was fabricated through CAE(Computer Aided Engineering) and 3D printing, which can adjust automatically the height of the pillow when lying sideways and backwards according to the sleeping posture. The target height difference of the pillow was about 1.0 cm ~ 1.5 cm when the head weight difference was about 1.2 kg. Instead of using a complex mechanical device, it was based on an arch structure made of TPU. From the simulation, the optimum model was designed through series combination and the results were compared with the experimental ones. The final product had a height difference of about 2 cm according to the lying posture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.581-586
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• 2018

Cast iron manhole lids cause environmental pollution during the manufacturing process, and the work environment is very poor. In addition, if the height of the manhole cover does not match the height of the road surface, it causes considerable inconvenience and safety problems. This study proposes a height - adjustable steel manhole cover that can replace cast iron manhole covers and easily match the road surface with the upper surface of the manhole cover. Structural analysis was performed to grasp the design variable of the structure of the manhole cover, satisfying the required quality performance. To fabricate a manhole cover that satisfies the required load capacity, the optimal design for the U-shaped reinforcement structure was made. The cylindrical shape of the height adjustment part and the low frame were formed by bending the steel sheet into a circular shape and then welding. Reinforcing bars were also made by bending a steel plate. The height adjustment groove was machined by a CNC milling machine. Four prototypes were fabricated and a load bearing test was carried out, and new manhole cover was made reflecting results of the test. In the load bearing test, there was no breakage of the welded part, and deformation occurred mainly at the contact area between the groove and gusset plate. Deformation of 1 to 2.7mm occurred due to a load of 450kN. On the other hand, after removing the load, there was almost no residual deformation, and the load bearing evaluation was judged to be satisfactory because the manhole cover could be disassembled and reassembled.

• Korean Journal of Human Ecology
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• v.16 no.6
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• pp.1243-1250
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• 2007

The purpose of this study was to compare government guidelines and foreign guidelines related to furniture design for elderly. Future elderly will increasingly accustomed to the provisions of improved housing, education and welfare in comparison with our forebears. Also, there will be upgrading and different need for elderly furniture in our market. The results were as follows. The height of bed was based on the height of wheelchair seat, commonly. A adjustable bed was recommended for abled and disabled elderly. A pull-down shelf, drawer, empty space under chest, folding or sliding door in wardrobe and so on were recommended as a elderly furniture. It were good adjustable sink on human scale. There were need the empty space under sink for wheelchair users, one-touch or lever faucet, etc. There have given a little furniture design guidelines for elderly in Korea until now. But those guidelines haven't been considered enough human scale of elderly including wheelchair user. Because the close investigations have not made about abled and disabled elderly for their furniture design. So first of all, the government should be examined elderly physical size more accurately for elderly furniture design. The guideline for elderly furniture design should be for abled elderly and the disabled, too.