• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.4
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• pp.87-93
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• 2021

The mold industry is competitive, and mold should be processed under optimal conditions for efficient processing. However, the cutting conditions of the ball-end mill, which are a major factor in mold processing, are mostly set empirically, and considerable research is required for increasing the tool life and processing accuracy. In this study, a tool dynamometer and an eddy current sensor were used along with NI-DAQ, a data acquisition device, to obtain characteristic values of the cutting force and tool deformation during the ball end-mill machining of inclined surfaces at a machining center. The cutting force and tool deformation were measured in an experiment. It was found that the tool received the greatest cutting force at the end of the machining process, and the deformation of the tool increased rapidly. Furthermore, the cutting force tended to increase with the angle and number of rotations. The deformation increased rapidly during the machining of a 45° inclined surface.

• Journal of the Korean institute of surface engineering
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• v.54 no.6
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• pp.324-330
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• 2021

As energy harvesting technology becomes important in relation to environmental issues, piezoelectric materials that convert mechanical energy into electrical energy are attracting attention. However, PZT, a representative material for piezoelectricity, is becoming difficult to use due to the problem that its components can cause environmental pollution. For this reason, recent research suggests a triboelectric nanogenerator (TENG) that generates energy through the combined effect of triboelectricity and electric induction for alternative piezoelectric devices. In TENG, electrical power is determined by the dielectric constant, thickness, and grain generation of the charged material. Therefore, in this study, a Rutile phase TiO₂ thin film with high dielectric constant was formed using the spin-coating process and the effect of annealing was investigated. For electrical analysis, a TENG device was fabricated using PTFE as a material with an opposite charge, and electrical output according to film thickness and grain formation was comparatively analyzed.

• Journal of Drive and Control
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• v.16 no.3
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• pp.8-15
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• 2019

Wheelchair users experience difficulty when using transportation. This is because wheelchair users must use transportation means together with wheelchairs. Therefore, in this paper, we developed a wheelchair storage system for passenger's car trunk. The mechanism is designed to allow a wheelchair and the device to be housed simultaneously in the narrow space of the trunk of the sedan passenger car. Additionally, this wheelchair storage system has implemented an initial load reduction mechanism that can mechanically reduce the initial load. This wheelchair storage system verified the system's operability through the production of the prototype. This system was actually installed in the trunk of the sedan passenger's car to verify the storage process. The operation and storage process of the wheelchair storage system was been perfectly verified. This wheelchair storage system will help a lot of self-driver or an assistant (female or elderly) who use wheelchairs.

• The Korean Journal of Emergency Medical Services
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• v.22 no.3
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• pp.67-76
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• 2018

Purpose: The purpose of this study was to evaluate the quality of chest compressions and ventilation when using an mechanical device(LUCAS) and 2-men manual cardiopulmonary resuscitation(CPR) performed on a minikin, as well as to propose a more effective CPR method during transit. Methods: Data were collected by LUCAS and manual virtual reality based ambulance simulation. Analysis was performed using SPSS software 12.0. The average and standard deviation of chest compression depth and ventilation were analyzed using descriptive statistics and t-test. Results: In the virtual reality based LUCAS and manual CPR results, LUCAS showed better chest compression and lower incomplete chest release than manual CPR. During CPR with a chest compression-ventilation ratio of 30:2 in virtual reality ventilation with bag-valve mask was able to deliver an adequate volume of breathing. Conclusion: It is suggested that rescuers on ambulance may consider using LUCAS as an alternative to high-quality chest compression during transit.

• Journal of Korean Biological Nursing Science
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• v.20 no.4
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• pp.228-235
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• 2018

Purpose: This study aimed to investigate the clinical alarm occurrence and management of nurses toward clinical alarms in the intensive care unit (ICU). Methods: This observational study was conducted with 40 patients and nurses cases in two ICUs of a university hospital. This study divided 24 hours into the unit of an hour and conducted two times of direct observation per unit hour for 48 hours targeting the medical devices applied to 40 patients. Data were analyzed using IBM SPSS Statistics 23. Results: On average, 3.8 units of medical devices were applied for each patient and the ranges of alarm settings were wide. During 48 hours, 184 cases of clinical alarm were occurred by four types of medical devices including physiological monitors, mechanical ventilators, infusion pumps, and continuous renal replacement therapy. Among them, false alarm was 110 cases (59.8%). As for the alarm management by ICU nurses, two-minute alarm mute took up most at 38.0% (70 cases), and no response was second most at 32.6% (60 cases). When valid alarm sounded, nurses showed no response at 43.2%. Conclusion: The findings suggest that a standard protocol for alarm management should be developed for Korean ICU settings. Based on the protocol, continuous training and education should be provided to nurses for appropriate alarm management.

• Smart Structures and Systems
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• v.24 no.2
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• pp.223-231
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• 2019

The properties of Electroactive Polymer (EAP) materials are attracting the attention of engineers and scientists from many different disciplines. From the point-of-view of robotics, Ionic Polymer Metal Composites (IPMC) belong to the most developed group of the EAP class. To allow effective design of IPMC-actuated mechanisms with large induced strains, it is necessary to have adequate analytical tools for predicting the behavior of IPMC actuators as well as simulating their response as part of prototyping methodologies. This paper presents a novel IPMC motor construction. To simulate the bending behavior that is the dominant phenomenon of motor movement process, a nonlinear model is used. To accomplish the motor design, the IPMC model was identified via a series of experiments. In the proposed model, the curvature output and current transient fields accurately track the measured responses, which is verified by measurements. In this research, a three-dimensional Finite Element Method (FEM) model of the IPMC motor, composed of IPMC actuators, simultaneously determines the mechanical and electrical characteristics of the device and achieves reliable analysis results. The principle of the proposed drive and the output signals are illustrated in this paper. The proposed modelling approach can be used to design a variety of controllers and motors for effective micro-robotic applications, where soft and complex motion are required.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.91-95
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• 2019

A new experimental approach is proposed to detect a specific polymer dissolved in a liquid. Distinctive optical properties were found using a laser scattering technique when there is a polymer compound with almost no difference in optical properties (index of refraction) in a liquid phase. The index of refraction, which determines the refraction of light, is obtained by dissolving PCL and PLA. The used samples are biodegradable materials with similar properties and dissolved in a mixture of Chloroform 7: Methanol 3. To predict the optical properties, a 632-nm diode laser was used as the light source of the device, and an integrating sphere was used as the light receiver. Although PCL and PLA had a similar index of refraction of 1.46-1.48, the dissolved PCL showed a relative transmittance of 43%, and the dissolved PLA had a relative transmittance of 34%. The difference in optical properties of the pure polymer compound in the solid state or liquid state is not significantly different, and the difference in the dissolved state in the specific solvent is remarkable because the solubility differs in a specific solution and is randomly distributed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.80-86
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• 2020

With the exception of welding activities, it is forbidden to use electricity in shipyards, owing to safety concerns such as the possibility of fire, explosions, and short circuits. In this paper, an automatic chamfering machine using pneumatics is proposed for use in such environments. Customers specify their requirements and the machine derives the corresponding theoretical design conditions. The proposed machine was used to perform 3D modeling, and its suitability and performance were confirmed via cutting experiments of the manufactured device. Two types of sensors may be used in this system: contact and non-contact. In the case of the contact type, an end-stop switch that can recognize the end of the material is installed, and when the machine reaches the end of the material, the end-stop switch is operated to cut off the air pressure. In the non-contact type, four sensors were used: photonic, ultrasonic, metal detection, and encoder. The use of the four sensors was repeated 30 times, and the average error determined. Thus, the optimum sensor was identified.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.101-106
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• 2021

In this paper, an inspection system has been developed where pneumatic instruments are used to stretch the film using compressed air, thus the curl problem can be overcome. When the pneumatic system is applied, a line scan camera should be used instead of an area camera because the COF surface makes an arc by the air pressure. The distance between the COF and the inspection camera should be kept constant to get a clear image, thus the position of COF is to be monitored on real-time. An operating software has been also developed which is switching on/off the pneumatic system, determining the COF position using a camera vision, displaying the contour of the COF side view, sending self-diagnosis result and etc. The developed system has been examined using the actual roll of COF, which convince that the system can be an effective device to inspect the COF rolls in process.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.170-174
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• 2021

As the rising attention to the medical and healthcare issue, Bio-MEMS (Micro electro mechanical systems) platform such as bio sensor, cell culture system, and microfluidics device has been studied extensively. Bio-MEMS platform mostly has high resolution structure made by biocompatible material such as polydimethylsiloxane (PDMS). In addition, three dimension structure has been applied to the bio-MEMS. Lithography can be used to fabricate complex structure by multiple process, however, non-rectangular cross section can be implemented by introducing optical apparatus to lithography technic. X-ray lithography can be used even for sub-micron scale. Here in, we demonstrated lines with round shape cross section using the tilted gold absorber which was deposited on the oblique structure as the X-ray mask. This structure was used as a mold for PDMS. Molded PDMS was applied to the cell culture platform. Moreover, molded PDMS was bonded to flat PDMS to utilize to the sub-micro channel. This work has potential to the large area bio-MEMS.