Jang-Keun Oh

Development of a Comprehensive Usability Testing and Analysis Framework for the Physical Interface Between Product and User

Objective: The present study developed a comprehensive usability testing and analysis framework based on a physical interface model of product and user and applied the proposed framework to usability testing of canister-type vacuum cleaner. Background: The development of a user-centered product design is important to satisfy customers who want to use the product with ease of use and to keep the manufacturer competitive in the market. Method: The proposed testing and analysis framework consists of (1) characterization of physical product-user interface, (2) preparation and administration of usability testing questionnaire, and (3) analysis and interpretation of usability testing results. A usability evaluation of five vacuum cleaners was planned and administered based on the proposed framework and its analysis produced detailed and overall usability testing results for various aspects such as tasks, usability criteria, and design components. Results: The testing results were further utilized to identify usability problems and preferred design features of the vacuum cleaners. Conclusion: The proposed usability testing and analysis framework was found effective to identify preferred features and problems of a product design in a systematic, holistic manner. Application: The proposed framework can be of effective use for practitioners of product design and development to obtain comprehensive, quantitative usability testing information in a systematic manner.

Noise Reduction Method and Sources of Cyclone Sound for Vacuum Cleaner

Cyclone is widely adopted in the vacuum cleaner, because of the simple structure, the high dust collection efficiency and its transparency feature, which can be shown to the customer. At past times, cyclone performance was represented by collection efficiency, flow rate, pressure drop etc. At recent times the noise problem is getting important as cyclone comes into home-appliances. In this paper, pressure drop of cyclone and it`s noise were measured at the variation of the cyclone structure and the main sources of cyclone peak noise was found by experimental and numerical analysis. In addition, the structure for peak noise reduction was suggested and it is beneficial both pressure drop and noise reduction.

Characteristics of Flow-Induced Noise in the Suction Nozzle of a Vacuum Cleaner with a Double-Blade Fan

The characteristics of noise generation in the suction nozzle of a vacuum cleaner are analyzed numerically and experimentally. First, the flow resistance induced by each element in the suction nozzle of a vacuum cleaner with a double-blade rotary fan is investigated numerically and its relation with flow-induced noise and suction performance is examined in an anechoic room. The flow resistance and vorticity in the suction nozzle are calculated, and it is found that they are closely related to flow-induced noise and that the upper limit of noise reduction is only 4 dBA. This upper limit can be achieved by changing the design of the brush nozzle. Two methods for noise reduction by enlargement of flow-inlet area and by optimization of the number of blades are tested. Finally, the effects of each method are verified experimentally.