• Current Optics and Photonics
• /
• v.6 no.4
• /
• pp.407-412
• /
• 2022

We report on a diode-laser-pumped mode-locked Yb:KGW laser system, which delivers ultrashort pulses down to 89 fs at a repetition rate of 63 MHz, with an average power of up to 5.6 W. A fiber-coupled diode laser at 981 nm, operated with a compact driver, is used to optically pump the gain crystal via an off-axis parabolic mirror. A semiconductor saturable-absorber mirror is used to initiate the pulsed operation. Laser characteristics such as the pulse duration, spectrum bandwidth, and output power are investigated by varying the intracavity dispersions via changing the number of bounces between negative-dispersive mirrors within the cavity. Short pulses with a duration of 89 fs, a center wavelength of 1,027 nm, and 3.6 W of output power are produced at a group-velocity dispersion (GVD) of -3,300 fs². As the negative GVD increases, the pulse duration lengthens but the output power at the single-pulse condition can be enhanced, reaching 5.6 W at a GVD of -6,600 fs². Because of pulse broadening at high negative GVDs, the highest peak intensity is achievable at a moderate GVD with our system.

• Advances in Computational Design
• /
• v.7 no.4
• /
• pp.345-369
• /
• 2022

Infectious disease emergency hospitals are usually temporarily built during the pneumonia epidemic with higher requirements regarding diagnosis and treatment efficiency, hygiene and safety, and infection control.This study aims to identify how the Building Information Modeling (BIM) + Industrialized Building System (IBS) approach could rapidly deliver an infectious disease hospital and develop site epidemic spreading algorithms. Coronavirus-19 pneumonia construction site spreading algorithm model mind map and block diagram of the construction site epidemic spreading algorithm model were developed. BIM+IBS approach could maximize the repetition of reinforced components and reduce the number of particular components. Huoshenshan Hospital adopted IBS and BIM in the construction, which reduced the workload of on-site operations and avoided later rectification. BIM+IBS integrated information on building materials, building planning, building participants, and construction machinery, and realized construction visualization control and parametric design. The delivery of Huoshenshan Hospital was during the most critical period of the Coronavirus-19 pneumonia epidemic. The development of a construction site epidemic spreading algorithm provided theoretical and numerical support for prevention. The agent-based analysis on hospital evacuation observed "arched" congestion formed at the evacuation exit, indicating behavioral blindness caused by fear in emergencies.

• Journal of Korean society of Dental Hygiene
• /
• v.24 no.1
• /
• pp.69-77
• /
• 2024

Objectives: The purpose of this study was to explore the general public's perception and status of oral muscle strength training, to develop age-appropriate educational media and training methods, and to promote the need for oral muscle strength training. Methods: Data were collected from 15 individuals across different age groups (young, middle-aged, and elderly) from December 2022 to February 2023 through focus group interviews, and they were conducted twice for each group in a face-to-face manner. Results: Four key categories were identified: lack of information, effectiveness of training, need for promotion, and factors necessary for implementation. The following themes emerged: lack of information, need for training, age-specific characteristics, need for repetition, age at which training is needed, lack of promotion, need for promotion, number of practitioners, willingness to practice, and appropriate media for training. Conclusions: Awareness of oral muscle strength training was found to be very low, and it is necessary to improve awareness through continuous information and appropriate education on its need among the public. Additionally, quality content or media that can be easily applied for effective training should be developed, and personnel who can perform training efficiently should be trained.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.665-668
• /
• 1997

We fabricated a number of optical fiber Bragg gratings by varying the UV beam parameters such as the laser energy density, pulse repetition rate and exposing time. The reflectance and the Bragg wavelength shift of the fiber Bragg gratings formed with a KrF excimer laser in real time depend strongly on the UV beam parameters. The index changes in the gratings during the exposing time are well fitted to the well known equations.

• Journal of Information Technology Services
• /
• v.20 no.6
• /
• pp.125-139
• /
• 2021

To explore college students' course satisfaction over the course of the semester during which a full-scale digital transformation was in progress due to COVID-19 pandemic, this study analyzed student survey data from a university located in the metropolitan area. To minimize the respondents' burden to answer long list of detailed questions in repetition, the study utilized a pulse survey method and students were asked to answer a brief and regular set of online questions 5 times throughout the semester. The number of survey respondents ranged from 1,640 to 4,116, with an average of more than 3,700. The main results and implications of this study are summarized as follows. First, the survey data indicated that the overall student satisfaction with online courses was above average (3.46/5). Vast majority of students have chosen pre-recorded, contents-based course over real-time, video-based course as their preferred course delivery method and this tendency remained the same throughout the semester. Second, the results of keyword network analysis of open-ended questions indicated that technical issues, increased workload (e.g., course assignments and course attendance) were main causes of online course dissatisfaction. And students suggested an unified online course platform and more interactive course design to further improve online courses in the future.

• The Research Journal of the Costume Culture
• /
• v.7 no.2
• /
• pp.315-322
• /
• 1999

The acquistion and dyeability of the Gardenia jasminoides were examined to establish the optimum condition for extraction and storage in the process of obtaining the natural dye, Gardenia jasminoides colorant. Also the dyeability and colorfastness of Gardenia jasminoides were investigated. The results of this study are as follows. The optimum part-removed seed. In all experiments, the part of fat-removed seed and pericarp was used. The optimum condition for extraction of Gardenia jasminoides colorant was at 40℃ and for 90 min. in methanol. As storage temperature was higher, the absorbance of colorant extract decreased rapidly. The Gardenia jasminoides colorant exhibited dyeability to cotton, silk, wool, and nylon. The dyeability was the greatest in wool, and then nylon, silk, and cotton. Both wool and nylon had the greatest K/S value at pH3, however, nylon and cotton at pH 6 and pH 8 respectively. In addition, the increase in K/S value corresponded to temperature in wool and nylon, but the silk and cotton had the greatest K/S value at 60℃. Also, the K/S value increased in concomitant with the increased number of dyeing repetition. In the most cases, colorfastness of light was weak but colorfastness of laundry, sweat was relatively excellent.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.5
• /
• pp.2322-2326
• /
• 2011

General cryptosystem uses differently the data and key value for the increment of security level, processes the repetition of limited number and increases the periodic feature of LFSR similar infinite series. So, it cause the efficiency of the cryptosystem. In this thesis, proposed algorithm is composed of reformat, permutation, data cipher block and key scheduler which is applied the new function by mixed symmetric cryptography and asymmetric cryptography. We design the cryptosystem of smart card using the common Synopsys and simulate by ALTERA MAX+PLUS II at 40MHz. Consequently, we confirm the 52% increment of processing rate and the security level of 16 rounds.

• Journal of Magnetics
• /
• v.17 no.1
• /
• pp.27-32
• /
• 2012

Transcranial magnetic stimulation requires an electric field composed of dozens of V/m to achieve stimulation. The stimulation system is composed of a stimulation coil to form the electric field by charging and discharging a capacitor in order to save energy, thus requiring high-pressure kV. In particular, it is charged and discharged in capacitor to discharge through stimulation coil within a short period of time (hundreds of seconds) to generate current of numerous kA. A pulse-type magnetic field is formed, and eddy currents within the human body are triggered to achieve stimulation. Numerous pulse forms must be generated to initiate eddy currents for stimulating nerves. This study achieved high internal pressure, a high number of repetitions, and rapid switching of elements, and it implemented numerous control techniques via introduction of the half-bridge parallel load method. In addition it applied a quick, accurate, high-efficiency charge/discharge method for transcranial magnetic stimulation to substitute an inexpensive, readily available, commercial frequency condenser for a previously used, expensive, high-frequency condenser. Furthermore, the pulse repetition rate was altered to control energy density, and grafts compact, one-chip processor with simulation to stably control circuit motion and conduct research on motion and output characteristics.

• Korean Journal of Applied Biomechanics
• /
• v.15 no.4
• /
• pp.75-83
• /
• 2005

The purpose of this study was to determine the kinematic characteristics of the ankle joint and RPM(repetition per minutes) during the supra maximal training in cycling. For this study, 8 national representative cyclists, distance cyclists in track and road, were selected. During the super-maximum pedalling, kinematic data were collected using a six-camera(240Hz) Qualisys system. the room coordinate system was right-handed and fixed in the back of a roller for cycle, with right-handed orthogonal segment coordinate systems defined for the leg and foot. Lateral kinematic data were recorded at least for 3 minutes while the participants pedal on a roller. Two-dimensional Cartesian coordinates for each marker were determined at the time of recording using a nonlinear transformation technique. Coordinate data were low-pass filtered using a fourth-order Butterworth recursive filter with cutoff frequency of 15Hz. Variables analyzed in this study were compared using a one factor(time) ANOVA with repeated measures. The results of investigation suggest that the number of rotating pedal was decreased with time phase during the super-maximum pedaling. Maximum angle of the ankle joint showed little in change with time phase compared with minimum angle of that.

• Journal of Convergence for Information Technology
• /
• v.11 no.11
• /
• pp.17-22
• /
• 2021

Radar signal analysis of electronic warfare is a technique for identifying a radar type by signal parameters(direction, radion frequency, pulse repetition interval, pulse width, scan period..) extracted from a received radar pulse. However as the modern radar and new threat environments is advanced, radar identification ambiguity arises in the process of identifying the types of radars. In this paper, we analyze the problems of the existing method and propose a new method. This technique determines the validity of the scan period by the difference in the arrival time of the radar pulse and the minimum number of scan period discrimination. Experiments proved that the scan cycle results are derived regardless of the RMS((Root Mean Square) of the input amplitude.