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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Manufacturing Technology Engineers
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Journal DOI :
The Korean Society of Manufacturing Technology Engineers
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Volume & Issues
Volume 22, Issue 6 - Dec 2013
Volume 22, Issue 5 - Oct 2013
Volume 22, Issue 4 - Aug 2013
Volume 22, Issue 3 - Jun 2013
Volume 22, Issue 3_1spc - Jun 2013
Volume 22, Issue 2 - Apr 2013
Volume 22, Issue 1 - Feb 2013
Selecting the target year
Cutting Force Variation Characteristics in End Milling of Terrace Volume
Maeng, Heeyoung ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 489~495
DOI : 10.7735/ksmte.2013.22.3.489
This study analyzed thevariation in the cutting force when the cutting area of a terrace volume is machined, which is generally left after the rough cutting of a sculptured surface. The numerically simulated results for the cutting forces are compared with cutting force measurements by considering the theoretical prediction of the cutting area formation and specific cutting volume. The variation in the cutting force is measured using a dynamometer installed on a machining center for 19 different kinds of test pieces, which are selected according to the variation in the terrace volume factor, tool diameter factor, and cutting depth factor. As a result, it is verified that the cutting forces evaluated by the numerical analysis coincide with the measured cutting forces, and it is proposed as a practical cutting force prediction model.
Tumor Detection Algorithm by using Mammogram Image Processing
Song, Kyohyuk ; Chon, Minhee ; Joo, Wonjong ; Kim, Gibom ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 496~503
DOI : 10.7735/ksmte.2013.22.3.496
Recently, the death rate owing to breast cancers has been increasing, and the occurrence age for breast cancers is lowering every year. Mammography is known to be a reliable detection method for breast cancers and works by detecting texture changes, calcifications, and other potential symptoms. In this research on breast cancer detection, candidate objects were detected by using image processing on mammograms, and feature analysis was used to classify candidate objects as benign tumors and malignant tumors. To find candidate objects, image pre-processing and binarization using multiple thresholds, and the grouping of micro-calcifications were used. More than 50 shape features and intensity features were used in the classification. The performance of the detection algorithm by using Euclidian distance method for benign tumors was 93%, and the classification error rate was approximately 2%.
Thermal Fatigue Analysis of Wafer Level Embedded SiP by Changing Mold Compounds and Chip Sizes
Jang, Chong Min ; Kim, Seong Keol ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 504~508
DOI : 10.7735/ksmte.2013.22.3.504
This paper describes in detail the life prediction models and simulations of thermal fatigue under different mold compounds and chip sizes for wafer-level embedded SiP. Three-dimensional finite element models are built to simulate the viscoplastic behaviors for various mold compounds and chip sizes. In particular, the bonding parts between a mold and silicon nitride (Si3N4) are carefully modeled, and the strain distributions are studied. Three different chip sizes are used, and the effects of the mold compounds are observed. Through the numerical studies, it is found that type-C, which has a relatively lower Young's modulus and higher CTE, has a better fatigue life than the other mold compounds. In addition, the
chip has a shorter life than the
A Study on the Rehabilitation Equipment for Knee Joint
Lee, Gui-Hyung ; Kim, Yong-Jin ; Park, Seok-Hyun ; Lee, Hyo-Sung ; Cho, Hyun-A ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 509~517
DOI : 10.7735/ksmte.2013.22.3.509
This paper presents upgraded equipment to assist a patient in rehabilitating of their knee-joint by themselves. A new automatic mechanism is suggested and developed in order to add functions for enforcing the leg muscles, which were absent in previous rehabilitation machines. Using the Pro-engineer software, we analyze the displacements and speeds of several moving points of the equipment during various planned exercises. In addition, an appropriate control panel for operation is developed. Three motors andthree motor drivers are used in a tilting part for the ankle joint, sliding guide part for the knee joint, and up-down moving part for the whole leg. Finally, various newly upgraded motions can be generated by controlling the three motors simultaneously. we show that by using this equipment, we can adjust the proper length of the equipment according to the user's height and the intensity of the rehabilitation exercise.
Reliability-Based Structural Integrity Assessment of Wall-Thinned Pipes Using Partial Safety Factor
Lee, Jae-Bin ; Huh, Nam-Su ; Park, Chi-Yong ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 518~524
DOI : 10.7735/ksmte.2013.22.3.518
Recently, probabilistic assessments of nuclear power plant components have generated interest in the nuclear industries, either for the efficient inspection and maintenance of older nuclear plants or for improving the safety and cost-effective design of newly constructed nuclear plants. In the present paper, the partial safety factor (PSF) of wall-thinned nuclear piping is evaluated based on a reliability index method, from which the effect of each statistical variable (assessment parameter) on a certain target probability is evaluated. In order to calculate the PSF of a wall-thinned pipe, a limit state function based on the load and resistance factor design (LRFD) concept is first constructed. As for the reliability assessment method, both the advanced first-order second moment (AFOSM) method and second-order reliability method (SORM) are employed to determine the PSF of each probabilistic variable. The present results can be used for developing maintenance strategies considering the priorities of input variables for structural integrity assessments of wall-thinned piping, and this PSF concept can also be applied to the optimal design of the components of newly constructed plants considering the target reliability levels.
Active Control of Impinging Jets Using Bifurcating Excitations
Kim, Jungwoo ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 525~530
DOI : 10.7735/ksmte.2013.22.3.525
The objective of the present study is to investigate the heat transfer characteristics of turbulent impinging jets with bifurcating excitations. Bifurcating excitations use the dual mode, dual frequency forcing, where an axial forcing frequency is equal to double the helical forcing frequency. Under the bifurcating excitation, the heat transfer significantly increases in one plane (bifurcating plane), while nearly no heat transfer occurs in the perpendicular plane (bisecting plane). This result is closely associated with the change in the vortical structures caused by the excitation.
Development of Automatic Wax-Ring Manufacturing System for Silk Coating
Cho, Young Hak ; Maeng, Heeyoung ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 531~536
DOI : 10.7735/ksmte.2013.22.3.531
An automatic wax-ring manufacturing system for silk coating was developed, which consisted of a container, pallet with a cooling part, injection port, and removing device. The removing device is a system to load, lift, and cut the wax-ring, which is widelyused for various silk-coating industrial purposes. A novel removing device equipped with a water cooling circulation system is proposed in this paper. It has the benefit of easy control, as well as the convenience of loading and unloading without the use of other equipment. Three-dimensional modeling techniques were adopted to develop integrated functions for the automatic wax-ring manufacturing system, which made it possible to confirm the smooth integration/interface of each part and the system's interrelations with other manufacturing systems.
An Experimental Study on Thermal Conductivity Change of Water-Al
Nanofluid with the Elapse of Time, Stirring, and Adding Dispersing Agent
Park, Dong-Uk ; Park, Chang Yong ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 537~543
DOI : 10.7735/ksmte.2013.22.3.537
nanofluid was manufactured, and its thermal conductivity was measured in this study. The measurement was performed at volumetric concentrations of 0.5%, 1%, 2%, and 3%, and the nanoparticle sizes were 20 nm and 70 nm. Experimental test equipment, using the transient hot wire method, was installed to measure the thermal conductivity of the nanofluid, and the measured results were confirmed by measuring pure water with a measurement error of 0.92% at
. The thermal conductivity enhancement ranged from 4.8% to 13.6% for the 20 nm particle size, and from 3.1% to 8.8% for the 70 nm particle size at a concentration range of 0.5% to 3%. The enhancement increased with a decrease in particle size and an increase in concentration. With the elapse of time after manufacturing the nanofluid, the thermal conductivity enhancement decreased significantly from 5 to 9 h, and this trend was measured under all of the measurement conditions. After 24 h, the enhancement ranged from 1.2% to 3.5% for the 20 nm particles, and from 0.6% to 2.3% for the 70 nm particles. The enhancement trends with the elapse of time were almost identical with and without stirring the nanofluid. SDBS (Sodium Dodecyl Benzene Sulfonate) was added as a dispersing agent, and the decrease in the thermal conductivity enhancement was delayed.
Effects of Grooved Surface with Nano-ridges on Silicon Substrate on Anisotropic Wettability
Lee, Dong-Ki ; Cho, Younghak ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 544~550
DOI : 10.7735/ksmte.2013.22.3.544
A grooved surface with anisotropic wettability was fabricated on a silicon substrate using photolithography, reactive ion etching, and a KOH etching process. The contact angles (CAs) of water droplets were measured and compared with the theoretical values in the Cassie state and Wenzel state. The experimental results showed that the contact area between a water droplet and a solid surface was important to determine the wettability of the water. The specimens with native oxide layers presented CAs ranging from
. The droplets on the specimens with a native oxide layer could be in the Cassie state because they had relatively smooth surfaces. However, the CAs of the specimens with thick oxide layers ranged from
. This indicated that the surface roughness for a specimen with a relatively thick oxide layer was higher, and the water droplet was in the Wenzel state. From the CA measurement results, it was observed that the wetting on the grooved surface was anisotropic for all of the specimens.
An Experimental Study on the Performance of Brazed Plater Heat Exchangers
Park, Hyun-Min ; Park, Chang Yong ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 551~557
DOI : 10.7735/ksmte.2013.22.3.551
The heat transfer performance and pressure drop characteristics of brazed-plate heat exchangers with 20 and 30 plates were experimentally measured and analyzed in this study. The mass flow rates of the heat exchangers with 20 and 30 plates were fixed at 0.6 and 0.9 kg/s for the low temperature side, respectively. The mass flow rate for the high temperature side was controlled from 0.2 kg/s to 1.2 kg/s. The inlet temperatures for the high and low temperature sides were
, respectively. The heat transfer characteristics were not influenced by the number of plates. The pressure drop at the heat exchanger with 30 plates was slightly higher than that with 20 plates. The values calculated from the correlations based on gasket plate heat exchangers were compared with the experimental results. It was found that the predicted Nusselt numbers for the gasket plate heat exchangers were about 5% to 20% lower than the measured Nusselt numbers for the brazed plate heat exchangers. However, a pressure drop comparison showed that the calculated pressure drops at the gasket plate heat exchangers were less than half of the measured pressure drops at the brazed plate heat exchangers.
Generation and Animation of Optimal Robot Joint Motion data using Captured Human Motion data
Bae, Tae Young ; Kim, Young Seog ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 558~565
DOI : 10.7735/ksmte.2013.22.3.558
This paper describes a whole-body (human body's) motion generation scheme for an android robot that uses motion capture device and a nonlinear constrained optimization method. Because the captured motion data are based on global coordinates and the actors have different heights and different upper-lower body ratios, the captured motion data cannot be used directly for a humanoid robot. In this paper, we suggest a method for obtaining robot joint angles, which allow the resultant robot motion to be as close as possible to the captured human motion data, by applying a nonlinear constrained optimization method. In addition, the results are animated to demonstrate the similarity of the motions.
Collision Simulation for the Coupler System of Rolling Stock
Maeng, Heeyoung ; Kim, Jin Seong ; Park, Yeong-Il ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 566~572
DOI : 10.7735/ksmte.2013.22.3.566
In this study, a collision simulator for rolling stock that considers the plastic deformation of the car body and the dynamic characteristics of a coupler system was developed using Matlab/Simulink. Normally, a coupler system has functions for both connecting the individual car bodies and absorbing the impact energy. A coupler system is composed of a rubber buffer, hydraulic buffer, and deformation tube elements. The coupler system should protect the car body and prevent damage when the shunt speed is less than 10 km/h, which is the regulation speed based on the safety rule for rolling stock. However, if the shunt speed is greater than 10 km/h, a car body is plastically deformed. Therefore, the modeling of the plastic deformation of a car body should be included in a simulator. This collision simulator can provide the design parameters for a coupler system and car body.
Investigation of Maximum External Pressure of Helically Coiled Steam Generator Tubes with Axial and Circumferential Through-Wall Cracks
Lim, Eun-Mo ; Huh, Nam-Su ; Choi, Shin-Beom ; Yu, Je-Yong ; Kim, Ji-Ho ; Choi, Suhn ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 573~579
DOI : 10.7735/ksmte.2013.22.3.573
Once-through helically coiled steam generator tubes subjected to external pressure are of interest because of their application to advanced small- and medium-sized integral reactors, in which a primary coolant with a relatively higher pressure flows outside the tubes, while secondary water with a relatively lower pressure flows inside the tubes. Another notable point is that the values of the mean radius to thickness ratio of these steam generator tubes are very small, which means that a thick-walled cylinder is employed for these steam generator tubes. In the present paper, the maximum allowable pressure of helically coiled and thick-walled steam generator tubes with through-wall cracks under external pressure is investigated based on a detailed nonlinear three-dimensional finite element analysis. In terms of the crack orientation, either circumferential or axial through-wall cracks are considered. In particular, in order to quantify the effect of the crack location on the maximum external pressure, these cracks are assumed to be located in the intrados, extrados, and flank of helically coiled cylinders. Moreover, an evaluation is also made of how the maximum external pressure is affected by the ovality, which might be inherently induced during the tube coiling process used to fabricate the helically coiled steam generator tubes.
Design of Manual Wheelchair with a Function of Bed Transfer
Ko, Hyunjun ; Kim, Namyeul ; Hyun, Jungguen ; Jeong, Woochul ; Kang, Mowon ; Kim, Jonghyeong ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 580~586
DOI : 10.7735/ksmte.2013.22.3.580
In general, manual wheelchairs have played important roles in moving patients from one place to another. However, patients have experienced discomfort getting on and off because of the need for physical assistance. This can be more serious if a patient has handicaps involving the arms or legs. In addition, it could be unpleasant for both the patient and assistant because of the need for extensive physical contact with each other. At times, a weak nurse feels that there is a risk when transferring a heavy patient from a bed to a wheelchair. In this paper, a new non-powered wheelchair is designed to assist in transferring a patient to their bed. This design considers the convenience of both the patient and assistant when the patient is transferred from a wheelchair to a bed and vice versa. The operation minimizes the physical contact between the assistant and the patient. The new wheelchair is also lightweight and portable compared with the normal popular wheelchair.
Development of Standing and Gait Assistive Wheelchair
Song, Chan Yang ; Yoon, Hyo Joon ; Lee, Chibum ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 587~592
DOI : 10.7735/ksmte.2013.22.3.587
Until recently, the primary users of wheelchairs were people with lower body disabilities. However, the number of patients recovering from accidents or surgery, as well as the number of elderly people using wheelchairs, is constantly increasing. This study examined the design and manufacture of standing and gait assist wheelchairs that assist temporary gait disturbed patients to take rehabilitation training and elderly people to engage in walking exercise. A kinematic analysis was used to select a drive motor and design a four-bar linkage mechanism for lifting the backrest vertically. Using a multibody dynamic simulation, detailed design was performed taking into consideration the spatial motion and partial interference, and the necessary push force and stroke of the linear actuator were also calculated. To ensure structural safety, the von-Mises equivalent stresses of the upper and lower brackets of the linear actuator were verified through a finite element analysis. The manufactured wheelchair was shown to operate successfully as intended, using the developed controller for the drive motors and linear actuator.
Manufacturing Test-bench for Developing Nanopositioner
Kwon, Ji Yong ; Park, Geun Je ; Ryu, Won Jin ; Lee, Chibum ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 593~599
DOI : 10.7735/ksmte.2013.22.3.593
In this study, a test-bench for developing and verifying a 1- or 2-axis nanopositioner was manufactured. Using this test-bench, adesigned and manufactured flexure stage based on an analysis can configure nanopositioning systems. A breadboard and fixture were fabricated to be equipped with various types of mechanisms and sizes of stages. The test-bench has linear encoders for calibrating sensors and verifying the orthogonality and parasitic motion of 2-axis nested-type nanopositioners. The controller was developed using LabVIEW and a TI microcontroller. A case study that exemplified the test bench for developing a nanopositioner by senior undergraduate students is shown.
Development of Ergonomic Walking Assistance Robot for the Elderly and the Infirm
Kim, Jung-Yup ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 600~606
DOI : 10.7735/ksmte.2013.22.3.600
This paper describes the development of a novel walking assistance robot for the elderly and infirm. In the case of simple walking assistance devices, the walking safety and effectiveness are somewhat low; hence, caregivers are frequently required. The walking assistance robot developed in this research is capable of securely and conveniently assisting a walking user by using electric motors and various devices without a caregiver. The main features include the following. First, the walking safety is improved by using a pelvis supporter, and the robot is able to follow the user effectively by means of ergonomic motion sensors and electric powered wheels. Second, it is possible to adjust the load applied to the lower body by adjusting the height of the pelvis supporter. Finally, it is possible to inform the approximate distance and direction of any obstacle around the robot using the sounds and vibrations for the blind and the hearing impaired. The performance of the developed walking assistance robot was successfully verified using a walking assistance test in a narrow-corridor environment.
Robot Driving System and Sensors Implementation for a Mobile Robot Capable of Tracking a Moving Target
Myeong, Ho Jun ; Kim, Dong Hwan ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 607~614
DOI : 10.7735/ksmte.2013.22.3.607
This paper proposes a robot driving system and sensor implementation for use with an education robot. This robot has multiple functions and was designed so that children could use it with interest and ease. The robot recognizes the location of a user and follows that user at a specific distance when the robot and user communicate with each other. In this work, the robot was designed and manufactured to evaluate its performance. In addition, an embedded board was installed with the purpose of communicating with a smart phone, and a camera mounted on the robot allowed it to monitor the environment. To allow the robot to follow a moving user, a set of sensors combined with an RF module and ultrasonic sensors were adopted to measure the distance between the user and the robot. With the help of this ultrasonic sensors arrangement, the location of the user couldbe identified in all directions, which allowed the robot to follow the moving user at the desired distance. Experiments were carried out to see how well the user's location could be recognized and to investigate how accurately the robot trackedthe user, which eventually yielded a satisfactory performance.
A Study on the Design and Manufacturing of the Blind System with Auto-controlled Illuminance
Jang, Chong Min ; Kim, Seong Keol ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 615~621
DOI : 10.7735/ksmte.2013.22.3.615
A blind system for window glass has been designed and manufactured as a CapStone Design project at Seoul National University of Science and Technology. This system automatically controls the interior illuminance to maintain a uniform temperature. The aim of this project was to support an air conditioning system and heating equipment to maintain a good indoor environment. Proportional integral differential (PID) control using cadmium sulfide (CdS) sensors was applied to control it. Polaroid film was attached to the new blind system to reflect sunlight. It was found that the system had the potential to reduce energy consumption and may be used with a building energy management system (BEMS).
Development of Thigh Muscular Strength Assistance Robot for Workers
Kim, Jung-Yup ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 22, issue 3_1spc, 2013, Pages 622~628
DOI : 10.7735/ksmte.2013.22.3.622
This paper describes the development of a thigh-muscle strength-assistance robot, which is a kind of wearable robot. For practicality and commercialization, we proposed three fundamental concepts: the reduction of the thigh-muscle strength, minimized degree of dependence on a powered actuator, and complete wearer safety. Based on these concepts, a spring and link bar mechanism was conceived as a novel idea. The movement of the thigh is transferred to the spring mechanism through the link bar; hence, the elastic force of the spring assists the thigh muscle. Using forse sensing resistor (FSR) sensors and a powered cam mechanism, the muscle assistance is automatically activated and deactivated according to the wearer's movement. The specific mechanisms of the robot are addressed in detail, and the effectiveness is verified by experiments.