• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.2
• /
• pp.117-132
• /
• 2023

Mobility as a Service(MaaS) is an integrated mobility service that enables flexible reservation and payments for various transportation services on one platform, including existing public transportation. To popularize MaaS, users need to be satisfied with the service, and the factors that lower satisfaction need to be improved. In this study, the structural equation model was used to identify the influence of factors on the overall satisfaction level. Improvement plans to increase user satisfaction were derived based on importance-satisfaction analysis and the decision tree model. The analysis revealed the level of connectivity in MaaS apps to be a significant factor that needs to be improved for a higher user satisfaction level of MaaS

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.47 no.2
• /
• pp.155-167
• /
• 2024

Distribution and logistics industries contribute some of the biggest GDP(gross domestic product) in South Korea and the number of related companies are quarter of the total number of industries in the country. The number of retail tech companies are quickly increased due to the acceleration of the online and untact shopping trend. Furthermore, major distribution and logistics companies try to achieve integrated data management with the fulfillment process. In contrast, small and medium distribution companies still lack of the capacity and ability to develop digital innovation and smartization. Therefore, in this paper, a deep learning-based demand forecasting & recommendation model is proposed to improve business competitiveness. The proposed model is developed based on real sales transaction data to predict future demand for each product. The proposed model consists of six deep learning models, which are MLP(multi-layers perception), CNN(convolution neural network), RNN(recurrent neural network), LSTM(long short term memory), Conv1D-BiLSTM(convolution-long short term memory) for demand forecasting and collaborative filtering for the recommendation. Each model provides the best prediction result for each product and recommendation model can recommend best sales product among companies own sales list as well as competitor's item list. The proposed demand forecasting model is expected to improve the competitiveness of the small and medium-sized distribution and logistics industry.

• The Journal of Korean Academy of Prosthodontics
• /
• v.19 no.1
• /
• pp.39-45
• /
• 1981

Distal-extension removable partial dentures have long been implicated in the increase in mobility and the destruction of the supporting structures of the primary abutment teeth. Various clasping systems have traditionally been used to retain distal extension removable partial dentures, and other designs have been proposed to minimize torquing forces on the abutment teeth. Most recent studies investigating the effects of removable partial dentures on abutment teeth have been performed in it laboratory setting. Results obtained from in vitro research have given dentists insight into removable partial denture design, but laboratory test model cannot be constructed that simulates actual functional or parafunctiona1 movements and forces. The purpose of this study was to clinically evaluate the degree of tooth mobility produced by two clasping systems (suprabulge type and infrabulge type) used for distal extension removable partial dentures. Akers clasp and R.P.I. system were selected for the evaluation, and four patients required a distal extension removable partial denture on the mandibular arch were selected for participation in the study. Two partial dentures were constructed in the same condition expect the design of clasp. All abutments in the study were mandibular first or second premolars. Measurements of mobility were made with a research tool designed by $M\"{u}hlemann$. This instrument, periodontometer, measures tooth mobility in the mouth by means of a dial gauge accurated to 0.01mm when the tooth is stressed with a force meter. Lingual and buccal deflection of abutment tooth was measured using buccal and lingual pressure. The amount of force applied was 500gm. Tooth mobility tests were made at four key stages; 1. Before insertion of the first removable partial denture, baseline mobility was establsihed. 2. After wearing of the first prosthesis, measurement was made at weekly intervals for 4 weeks. 3. The removable partial denture was then taken from the patient, and tooth mobility was measured again at weekly intervals until the patient's established baseline mobility had returned. 4. The second prosthesis of different clasp design was worn for a month and evaluated in the same manner as the first. The sequence of placement of clasping system was alternated between patients. The following results were obtained from this study; 1. The mobility of abutment tooth increased during the initial stage of wear and returned to baseline mobility after removal of removable partial dentures. 2. The mobility of abutment tooth showed no difference between Akers clasp and I-bar clasp during the 4-week test period. 3. All teeth tested showed greater mobility toward the buccal than the lingual direction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.7
• /
• pp.343-353
• /
• 2018

Most local governments operate Mobility Support Centers to provide transportation convenience for the transportation vulnerable. A Mobility Support Center makes various efforts to improve the mobility of the transportation vulnerable. One of them is the operation of a Special Transportation Vehicle (STV). On the other hand, during implementation, problems, such as insufficient number of vehicles and high demand, have been found. Nevertheless, improving the service by providing a large amount of STV can be a problem in terms of the budget. Therefore, it is necessary to gather opinions of the users and identify the problems during the utilization of a Mobility Support Center. Moreover, it is necessary to improve various services to achieve a better and more comfortable utilization. In this research, SEM was used to analyze the importance of the Mobility Support Center for the transportation vulnerable. The importance and performance drawn and examined through an analysis and questionnaire survey were used to propose IPA results that consider the importance and performance at the same time. In addition, this research also suggest a service improvement priority based on the analysis result. For the analysis, this research conducted a questionnaire survey on the actual users and their guardians who use STV in Cheonan-city, as well as factor analysis and reliability analysis. The results showed that the 'Charge system' is not affected by the service because it is fully satisfied by the low price when compared to public transportation. In addition, 'Vehicle use' is more important than 'Convenience' service. IPA analysis showed that it is necessary to improve the priority, kindness, waiting time, and call center response for the better and more comfortable utilization of Mobility Support Centers for the transportation vulnerable.

• Architectural research
• /
• v.9 no.2
• /
• pp.1-9
• /
• 2007

As aging is notably developed, the elderly find it challenging to get around in housing chosen in their midlife, and seek for an alternative residential setting enabling them to continue the independent living. This research focuses on the residential mobility of the elderly who have recently moved to senior housing, and also is to investigate their residential satisfaction at previous residence. As a cross-sectional study, the research adopts the self-administered questionnaire survey. The questionnaires are mailed out, and one out of the two responses is retrieved. To investigate the residential mobility of the elderly, the research model is constructed based upon Morris and Winter's Housing Adjustment Theory. The result shows that the residential mobility of elderly from previous residence is a need-based choice, want-driven behavior and demand-oriented decision to maintain continued independence and utilize resources available during the aging process. Also, it is found that the vast majority of both co-op and rental households are satisfied with their previous residential environment. The previous residential satisfaction of co-op elderly is significantly influenced by household and housing characteristics, housing norm status, and environmental needs for independent living while only housing norm status is a significant predictor to explain the previous residential satisfaction of rental elderly.

• Journal of Internet Computing and Services
• /
• v.8 no.3
• /
• pp.57-63
• /
• 2007

Providing the sufficient energy to the mobile device is essential to process the job in distributed wireless network. To solve the restrained conditions of energy problems of mobile devices, this paper suggests the efficient method of processing the distributed job using mobility management in wireless network. Energy consumption can be analyzed using the statistical model and required energy of processing the distributed job in mobile device can be predicted using the mobility management. Therefore, this paper suggests the reliable algorithm to process distributed job through the mobile devices with regular mobility and shows the efficiency of the suggested algorithm.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.164.2-164.2
• /
• 2014

In order to combine advantages of ZnO thin film transistors (TFTs) with a high on-off ratio and graphene TFTs with extremely high carrier mobility, we present a facile methodology for fabricating ZnO thin film/graphene hybrid two-dimensional TFTs. Hybrid TFTs exhibited ambipolar behavior, an outstanding electron mobility of $329.7{\pm}16.9cm^2/V{\cdot}s$, and a high on-off ratio of $10^5$. The ambipolar behavior of the ZnO/graphene hybrid TFT with high electron mobility could be due to the superimposed density of states involving the donor states in the bandgap of ZnO thin films and the linear dispersion of monolayer graphene. We further established an applicable circuit model for understanding the improvement in carrier mobility of ZnO/graphene hybrid TFTs.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.6 no.3
• /
• pp.189-198
• /
• 2006

A new analytical model has been proposed for predicting the sheet carrier density of Metal insulator Semiconductor High Electron Mobility Transistor (MISHEMT). The model takes into account the non-linear relationship between sheet carrier density and quasi Fermi energy level to consider the quantum effects and to validate it from subthreshold region to high conduction region. Then model has been formulated in such a way that it is applicable to MESFET/HEMT/MISFET with few adjustable parameters. The model can also be used to evaluate the characteristics for different gate insulator geometries like T-gate etc. The model has been extended to forecast the drain current, conductance and high frequency performance. The results so obtained from the analysis show excellent agreement with previous models and simulated results that proves the validity of our model.

• The Journal of Korea Robotics Society
• /
• v.14 no.4
• /
• pp.357-362
• /
• 2019

This paper proposes a model and train method that can real-time detect objects and distances estimation based on a monocular camera by applying deep learning. It used YOLOv2 model which is applied to autonomous or robot due to the fast image processing speed. We have changed and learned the loss function so that the YOLOv2 model can detect objects and distances at the same time. The YOLOv2 loss function added a term for learning bounding box values x, y, w, h, and distance values z as 클래스ification losses. In addition, the learning was carried out by multiplying the distance term with parameters for the balance of learning. we trained the model location, recognition by camera and distance data measured by lidar so that we enable the model to estimate distance and objects from a monocular camera, even when the vehicle is going up or down hill. To evaluate the performance of object detection and distance estimation, MAP (Mean Average Precision) and Adjust R square were used and performance was compared with previous research papers. In addition, we compared the original YOLOv2 model FPS (Frame Per Second) for speed measurement with FPS of our model.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1390-1393
• /
• 2005

The hardening model based on the dislocation mechanics is employed to study the experimentally observed high tensile elongations of NiAl along the [110] orientation at intermediate temperatures. In the hardening model proposed, a mobility of dislocation is assumed to be restricted to glide through the slip plane by forest dislocation and thermally activated cross-slip event. Overall deformation behavior of NiAl was greatly influenced by temperature-dependent dislocation mobility that both experimental and simulated yield stresses decreased as temperature increased. The results of simulation showed anomalous hardening behaviors analogous to those of experiment at certain circumstances. This behavior occurred due to the hardening contributions generated by cross-slip events that disable the dislocation motion in the primary slip systems. By comparing simulation results with experiments, it is confirmed that the proposed hardening model can represent anomalous tensile elongations due to the hardening by forest dislocations and cross-slip events.