• Journal of IKEEE
• /
• v.25 no.1
• /
• pp.95-100
• /
• 2021

If we know the location of the hull block and the welding feeder in the shipyard, we can easily obtain the location information of the worker. That data is very useful for implementing a workplace safety monitoring system. However, it is difficult to apply a fixed communication network to the workplace due to the specificity of the hull structure and welding process. In this study, inductive power line communication, which can replace dedicated communication line, was reviewed. A ferrite core was used as an inductive coupler to be installed on the power cable of the welding machine, and a nano-crystalline core was applied as a coupler to be fastened to the support rod of the metal block. In order to visualize the operating principle of the proposed couplers, 3D modeling and finite element analysis were performed with the COMSOL AC/DC module. In the communication performance test using an aluminum profile, when the communication channel was formed by the contact of the welding electrode, the bandwidth was kept above 6 Mbps.

• Communications of Mathematical Education
• /
• v.34 no.4
• /
• pp.485-506
• /
• 2020

The purpose of this study is to analyze of the effect in Mathematics Teachers beliefs on their students beliefs by Latent Class Regression Model (LCRM). For this analysis, the study used the findings and surveys of Kang, Hong (2020) who developed a belief profile by analyzing the mathematical beliefs of 60 high school teachers and 1,850 second-year high school students learning from them through the Latent Class Analysis (LCA). As a result It was observed that 'Nature of Mathematics', 'Mathematic Teaching' and 'Mathematical Ability' of mathematics teachers beliefs influence the mathematical beliefs of students. The teacher's belief of 'Nature of Mathematics' statistically significant effects on students' beliefs in 'School Mathematics', 'Problem Solving', 'Mathematics Learning'. The teacher's belief of 'Teaching Mathematics', 'Mathematical Ability' statistically significant effects on students' beliefs in 'School Mathematics', 'Problem Solving', 'Self-Concept'. The results of this study can give a preview of the phenomenon in which teacher's mathematical beliefs are reproduced into student's mathematical beliefs. In addition, the results of observation of this study can be used to the contents that can achieve the purpose of reorientation for mathematics teachers.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1278-1282
• /
• 2009

In apartment type of housing, if resident's vehicle is registered in central control office and RFID TAG is issued, identification can be recognized from the time of entrance into parking lot and intelligent parking guide system can be activated based on the residents' profile. Parking Guide System leads a vehicle to the available parking space which is closest to the entrance gate of the vehicle's owner. And when residents forget where they parked their cars, they can query to the Parking Guide and Management System and get responses about the location. For the correct operation of this system, it is necessary to find out where the residents' cars have parked in real time and which lot is available for parking of other cars. RFID is very fancy solution for this system. RFID reader gathers the ID information in RFID TAGs in parked cars and updates the DB up to date. But, when non-residents' cars are parked inside apartment, RFID reader cannot identify them nor know the exact empty/occupied status of parking spaces because they don't react to RFID reader's query. So for the exact detection of empty/occupied status, we suggest the combined use of ultrasonic sensors and RFID. We designed a tree topology with intermediate data aggregators. The depth of tree is normally more than 3 from root (central office) to leaves (individual parking lots). The depth of 2 in tree topology brings about the bottleneck in communication and maintenance. We also designed the information fields used in RFID networks and Sensor Networks.

• Annals of Hepato-Biliary-Pancreatic Surgery
• /
• v.26 no.4
• /
• pp.318-324
• /
• 2022

Backgrounds/Aims: Gallstone disease is a recognized complication of bariatric surgery. Subsequent management of choledocholithiasis may be challenging due to altered anatomy which may include Roux-en-Y gastric bypass (RYGB). We conducted a retrospective service evaluation study to assess the safety and efficacy of endoscopic ultrasound-directed transgastric endoscopic retrograde cholangiopancreatography (EDGE) in patients with RYGB anatomy. Methods: All the patients who underwent EDGE for endoscopic retrograde cholangiopancreatography after RYGB at two tertiary care centers in the United Kingdom between January 2020 and October 2021 were included in the study. Clinical and demographic details were recorded for all patients. The primary outcome measures were technical and clinical success. Adverse events were recorded. Hot Axios lumen apposing metal stents measuring 20 mm in diameter and 10 mm in length were used in all the patients for creation of a gastro-gastric or gastro-jejunal fistula. Results: A total of 14 patients underwent EDGE during the study period. The majority of the patients were female (85.7%) and the mean age of patients was 65.8 ± 9.8 years. Technical success was achieved in all but one patient at the first attempt (92.8%) and clinical success was achieved in 100% of the patients. Complications arose in 3 patients with 1 patient experiencing persistent fistula and weight gain. Conclusions: In patients with RYGB anatomy, EDGE facilitated biliary access has a high rate of clinical success with an acceptable safety profile. Adverse events are uncommon and can be managed endoscopically.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.5
• /
• pp.491-503
• /
• 2014

In this paper, a $TM_{31}$ higher order mode half circular-ring microstrip antenna with monopole-like radiation characteristic for on-body communication is proposed. By using shorting vias, $TM_{31}$ resonance mode was excited, while achieving compact low-profile antenna with monopole-like radiation characteristics. To overcome the narrow bandwidth of a patch antenna, a C-shape half ring patch with shorting vias having $TM_{31}$ mode is closely located around a half circular patch. For size reduction, half mode is adopted. The proposed antenna has the overall dimensions of $0.25{\lambda}_0{\times}0.46{\lambda}_0{\times}0.025{\lambda}_0$ at the industrial, scientific, and medical(ISM) 2.45 GHz band(2.4~2.485 GHz) and the 10-dB return loss is 4.24 % ranging from 2.38 to 2.49 GHz. To verify body effect, two-thirds muscle equivalent semi solid phantom was fabricated and used to measure the antenna performance. A communication link is analysed to investigate the effect of human-body movements and antenna locations.

• The Journal of Society for e-Business Studies
• /
• v.15 no.2
• /
• pp.37-53
• /
• 2010

As mobile communications service is growing every single year in Korea, it has pulled the interest of many researchers as wells as the executives. This research is aimed to find out factors of the mobile market that affect the utilization of mobile communication. We adopted a survey method with a pinpointed focus on how users' profile and individual experience relates with the utilization of mobile communication. For this objective, first, we primarily analyzed the mobile users' characteristics and service usage patterns. Then, we developed a conceptual model and hypotheses that are empirically examined using a covariance structure analysis, which will contribute to investigating critical success factors in mobile business. Some suggestions constitute the remaining part of this research. First, user characteristic is an important factor that affects the amount expended for mobile service. Second, user experience is another critical aspect that is highly linked with mobile payment. In alignment with our research, we propose user characteristics such as age and income, and user experience about mobile internet usage and mobile contents usage are of great significance in devising both near- and long-term mobile business strategy.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.7B
• /
• pp.613-627
• /
• 2004

In this paper, we propose an Aggregate Fairness Maker (ARM) required for an Edge router to improve fairness of throughput among the flows of Assured Service in DiffServ with different round trip time (RTT) and we propose a user flow Three Color Marker (uf-TCM) as a flow marker that marks packets from the flow as green, yellow, or red. A yellow packet is the packet that consumes loss token in uf-TCM as well as that is demoted green packet in AM due to disobey the aggregate traffic profile. The proposed AFH promotes yellow packet to green packet or demotes green packet to yellow packet through the fair method without per-flow management, and it improves the feirness of throughput among the flows as well as link utilization. A yellow packet and a red packet have the same drop precedence at Core Router in our scheme. So we can use the RIO buffer management scheme. We evaluated the performance of our proposed AFM and the REDP Marker that was proposed to improve fairness without per-flow management. Simulation results show that, compared with the REDP marker, proposed AFM can improve performance of throughput fairness among the flows with different RTT and link utilization under the over-provisioning, exact-provisioning, and under-provisioning network environments at Multiple DiffServ domains as well as at Single DiffServ domain.

• Communications of Mathematical Education
• /
• v.34 no.1
• /
• pp.17-39
• /
• 2020

The purpose of this study is to analyze the mathematical beliefs of students and teachers by Latent Class Analysis(LCA). This study surveyed 60 teachers about beliefs of 'nature of mathematics', 'mathematic teaching', 'mathematical ability' and also asked 1850 students about beliefs of 'school mathematics', 'mathematic problem solving', 'mathematic learning' and 'mathematical self-concept'. Also, this study classified each student and teacher into a class that are in a similar response, analyzed the belief systems and built a profile of the classes. As a result, teachers were classified into three types of belief classes about 'nature of mathematics' and two types of belief classes about 'teaching mathematics' and 'mathematical ability' respectively. Also, students were classfied into three types of belief classes about 'self concept' and two types of classes about 'School Mathematics', 'Mathematics Problem Solving' and 'Mathematics Learning' respectively. This study classified the mathematics belief systems in which students were categorized into 9 categories and teachers into 7 categories by LCA. The belief categories analyzed through these inductive observations were found to have statistical validity. The latent class analysis(LCA) used in this study is a new way of inductively categorizing the mathematical beliefs of teachers and students. The belief analysis method(LCA) used in this study may be the basis for statistically analyzing the relationship between teachers' and students' beliefs.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.6A
• /
• pp.585-593
• /
• 2010

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure local location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of sinks. Most existing geographic routing protocols merely assume that source nodes are aware of the locations of sinks. How can source nodes get the locations of sinks was not addressed in detail. In this paper, we propose a sink location service via circle path for geographic routing in wireless sensor networks. In this scheme, a sink sends a Sink Location Announcement (SLA) message along a circle path, and a source node sends a Sink Location Query (SLQ) message along a straight path that certainly passes through the circle path. By this way we can guarantee the SLQ path and SLA path have at least one crossing point. The node located on the crossing point of the two paths informs the source node the sink location. This procedure can correctly work in any irregular profile sensor networks such as network that has holes or irregular shape by some rules. Simulation results show that our protocol is superior to other protocols in terms of energy consumption and control overhead.

• Journal of Music and Human Behavior
• /
• v.3 no.2
• /
• pp.29-44
• /
• 2006

Trust and understanding relationship promoted between a therapist and a client is the basic building block to successful recovery. Its importance is not only pertaining to the music therapy but also to counseling and psychological therapy. Because of its gnificance, broad spectrum of research has been conducted for quite a long time. Historically, researches have been focused on therapists or client's chological variables rather than emotional effects on each other that occur during the therapy session. Recently researchers turned their attention to emotional relationship between a therapist and a client. With recent advances in the field of music and psychological therapy, subsequent study has been conducted to investigate the role that music plays in the therapeutic relationship. For this research, eleven music therapy sessions were conducted for the adult females who are alcoholics. The first three sessions were of group therapy. Fourth to eleventh therapy session was done individually. Throughout the research case-by-case study has been conducted on the basis of the analysis of video and audio taped materials. Analysis depends heavily on its reference from the Amir's music research of 1990, which used Ferrara's seven phases of phenomenological study. Especially, verbal and nonverbal communications were closely analyzed in musical perspective. Research revealed that music and musical instruments act as a mediator between a therapist and a client. By doing so, it protects a therapist from unnecessary negative emotional displacements of a client and creates mutual reliability between a therapist and a client. Here, research suggests that music and musical instrument play a central role in building relationship between a therapist and a client, and it indicates that it has positive effect on treatment.