• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.10 s.175
• /
• pp.174-185
• /
• 2005

This paper presents the design, fabrication, and testing results of a dual stage actuator system for a fine positioning of magnetic heads in magnetic disk drives. A novel rotary microactuator which is electrostatically driven and utilized as a secondary actuator was designed. The stator and rotor electrodes in the microactuator was revised to have the optimal shapes and hence produces much higher rotational torque compared with the conventional comb-shape electrodes. The microactuators were successfully fabricated using SoG(silicon on glass) processing technology, which is known as being cost-effective. The fabricated microactuator has the structural thickness of $45{\mu}m$ with the gap width of approximately $3{\mu}m$. The dynamic characteristic of microactuator/slider assembly was investigated, and its natural frequency and DC gain were measured to be 3.4kHz and 32nm/V, respectively. The microactuator/slider assembly was integrated into a HDD model V10 of Samsung Electronics Co. and a dual servo algorithm was tested to explore the tracking performance of dual stage actuator system where the LDV signals instead of magnetic head signals were used. Experimental results indicate that this system achieves the tracking accuracy of 30nm. This value corresponds to a track density of 85,000 track per inch(TPI), which is about 3 times greater than that of current hard disk drives.

• Korean Journal of Head & Neck Oncology
• /
• v.2 no.1
• /
• pp.23-31
• /
• 1986

During the past 14years 267 patients presented with a lump in the neck proven to be metastatic cancer histologically. In most cases the primary site was discovered by thorough physical examination, E.U.A.(examination under anesthesia) and radiodiagnostic studies. However in 31 cases complete diagnostic evaluation failed to reveal the primary site. This paper discusses the characteristics of this group of patients in terms of the frequency of the ultimately discovered primary sites, policies for diagnosis, methods of management, and the ultimate prognosis for such cases in Korea. The male: female ratio was 6.8:1 and 84 % of all cases occurred in the $51{\sim)70$ age group. The majority of these cancers were epidermoid carcinomas(67.7%) and 22 of the 31(71 %) were Stage IV lesinos(17 N3A lesions and 5 N3B lesions). Surgical management was employed in 7 cases only, and in 5 cases this was combined with rediotherapy, chemotherapy, or both. Nevertheless, the only patients who survived disease-free for two years or more (one for over 5 years) were two patients in this management group. None of the patients treated by radiotherapy or chemotherapy of a combination of these two modalities survived. Occult primary sites were eventually discovered in 5 of the 31 cases, two in the nasopharynx, and one each in the base of tongue, pyrifrom sinus, middle ear. Of the 21 cases with epidermoid carcinoma which presented in the neck, 2 are free of disease for 3years or more. Of those who underwent radical surgery two of five survived. This study thus confirms the principle enunciated by MacComb in 1972 that surgical treatment in the form of radical neck dissection is the cornerstone of management whenever feasible.

• The Journal of the Acoustical Society of Korea
• /
• v.25 no.8
• /
• pp.362-369
• /
• 2006

In this paper, we improve a Physical modeling of sanio gayageum and synthesize sounds by right-hand playing styles. Parameters of loop filter are estimated from decay region of recorded sound. That results in improved accuracy and reduction of computational costs. Body is implemented to a resonator which has characteristics of main resonances extracted from impulse response. Residual signal with main resonances removed is used as excitation signal of proposed model. Amok alter is approximated to frequency response of amok and is implemented to the 15th order all-role digital filter. Beating (by middle and index finger) among the right-hand playing styles is represented by feedforward comb filter. Parameters of this filter are extracted from recorded sound. The synthesized sounds using improved physical model of sanjo gayageum. plucking and beating, are pretty similar to original sounds.

• Journal of Service Research and Studies
• /
• v.14 no.2
• /
• pp.48-68
• /
• 2024

Due to the global pandemic aftermath of the coronavirus, the importance of health care is being emphasized more socially. Due to the influence of these changes, domestic pharmaceutical companies have introduced regular drug delivery services, that is, drug and health functional food subscription services. Currently, this market is continuously growing. However, these regular services are causing new environmental problems in which the number of waste drugs increases due to the presence of unused drugs. Therefore, this study proposes a service that not only promotes health management through regular medication adherence to reduce the amount of pharmaceutical waste but also aims to improve awareness and practices regarding proper medication disposal. As a preliminary survey for service design, a preliminary survey was conducted on 51 adults to confirm their perception of drug use habits and waste drug collection. Based on the Honey Comb model, a guideline for service design was created, and a prototype was produced by specifying the service using the preliminary survey results and service design methodology. In order to verify the effectiveness of the prototype, a first user task survey was conducted to identify the problems of the prototype, and after improving this, a second usability test was conducted on 49 adults to confirm the versatility of the service. Usability verification was conducted using SPSS Mac version 29.0. For the evaluation results of the questionnaire, Spearmann Correlation Analysis was conducted to confirm the relationship between frequency analysis and evaluation items. This study presents specific solutions to the problem of waste drugs due to the spread of drug subscription services.