• The Journal of the Korea Contents Association
• /
• v.22 no.9
• /
• pp.1-18
• /
• 2022

This study critically analyzed the user experience (UX) of mobile applications, focusing on the advertising platforms of mobile applications for culture and arts content. This study aims to examine the direction for growth of the related mobile applications and propose alternative approaches to improve usability. In this study, a mobile app named 'Moviepre' was selected, and a heuristic evaluation was performed for in-depth exploration. For the selected case, the UX Honeycomb model was reconstructed to analyze useful, usable, desirable, findable, accessible, and credible elements of the case. First, since the users' preference for the price factor did not show a significant correlation with the usefulness of the content and the interface, it is necessary to make sure that the mobile application has unique values to gain a competitive advantage in the market. Second, by adopting customer path stages for analysis, the result indicated that users continuously interact with the service from the first moment they are aware of the mobile application. Third, if the user feels uncomfortable, it is likely that these factors hinder the establishment of a long-term relationship between the users and the mobile application. Finally, brand identity should be clearly established, and brand image strategy needs to be developed to satisfy users' expectations that high-quality culture and arts content will be available through the mobile application.

• 한국노년학
• /
• v.30 no.4
• /
• pp.1197-1211
• /
• 2010

This research was concucted to present a model of advance directives(AD) when a patient, who is in consciousness, shows a preference for an end of life care as an act of preparing for an uncertain situation that may arise in the forseeable future. The subjects of the research are 383 doctors/nurese and adults, who live in six cities and provinces, to investigate the status of AD, attitude regarding a meaningless life-prolonging treatment, and moreover, an understanding of and a preference for AD. The research was done by the well-structured questionnaire. Also, SPSS 14.0 is used to analyse the collected data, focused on frequency analysis, avearage and standard deviation, X2 test. As the results of the study, the most of the surveyed doctors/nurese knew DNR orders and AD and a few of them used DNR orders and AD practically. Also, the result shows that there is a negative conception of meaningless life-prolonging treatment among the responents, in addition, most of them agreed upon the idea of introducing AD to Korea, filling it out and making it legally effective. As a method of making AD out, the respondents wanted to use a form that mixed living will with an Power of Attorney in a document. Also, considering the appropriate time, respondents prefered when they are diagnosed with terminal illness. At the moment, the introductory model for AD, which is suitable for the Korean culture and current situation is presented based on the result of this research. In the future, other researches should deal with specific measures that can lead to a social consensus to adopt AD in Korea.

• Journal of Navigation and Port Research
• /
• v.35 no.10
• /
• pp.823-827
• /
• 2011

The present Common Structural Rules for double hull oil tanker is not included the residual strength, which is one of the functional requirements in design part of Goal-based new ship construction standards (GBS). The GBS will be enforced after July 1, 2016. The requirement related residual strength has the goal to build safe ship even if she has the specified damages due to marine accidents including collision and grounding. In order to assess the residual strength based on risk for structural damages according to GBS, tons of nonlinear FE analysis work taking into account various types of damage will be needed. The Smith's method, a kind of simplified method for the strength analysis is very useful for this purpose. In this paper, the residual strength assessments based on ultimate strength using Smith's method were carried out. The objected ship is VLCC with stranding damage in bottom structures. Also, the results were compared with that of nonlinear FE analysis using three cargo hold model.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.16 no.4
• /
• pp.180-195
• /
• 2011

A balanced trophic model for Sinjido marine ecosystem was constructed using ECOPATH model and data obtained 1994 in the region. The model integrates available information on biomass and food spectrum, and analyses ecosystem properties, dynamics of the main species populations and the key trophic pathways of the system, and then compares these results with those of other marine environments. The model comprises 17 groups of benthic algae, phytoplankton, zooplankton, gastropoda, polychaeta, bivalvia, echinodermata, crustacean, cephalopoda, goby, flatfish, rays and skates, croaker, blenny, conger, flatheads, and detritus. The model shows trophic levels of 1.0~4.0 from primary producers and detritus to top predator as flathead group. The model estimates total biomass(B) of 0.1 $kgWW/m^2$, total net primary production(PP) of 1.6 $kgWW/m^2/yr$, total system throughput(TST) of 3.4 $kgWW/m^2/yr$ and TST's components of consumption 7%, exports 43%, respiratory flows 4% and flows into detritus 46%. The model also calculates PP/TR of 0.012, PP/B of 0.015, omnivory index(OI) of 0.12, Fin's cycling index(FCI) of 0.7%, Fin's mean path length(MPL) of2.11, ascendancy(A) of 4.1 $kgWW/m^2/yr$ bits, development capacity(C) of 8.2 $kgWW/m^2/yr$ bits and A/C of 51%. In particular this study focuses the analysis of mixed trophic impacts and describes the indirect impact of a groupb upon another through mediating one based on 4 types. A large proportion of total export in TST means higher exchange rate in the study region than in semi enclosed basins, which seems by strong tidal currents along the channels between islands, called Sinjido, Choyakdo and Saengildo. Among ecosystem theory and cycling indices, B, TST, PP/TR, FCI, MPL and OI are shown low, indicating the system is not fully mature according to Odum's theory. Additionally, high A/C reveals the maximum capacity of the region is small. To sum up, the study region has high exports of trophic flow and low capacity to develop, and reaches a development stage in the moment. This is a pilot research applied to the Sinjido in terms of trophic flow and food web system such that it may be helpful for comparison and management of the ecosystem in the future.

• Journal of Korean Home Economics Education Association
• /
• v.28 no.4
• /
• pp.123-137
• /
• 2016

This study's aim is to examine child's life competency that middle high school parents perceive and study the influence of parenting stress, parent efficacy, depression, parent education participation on child's life competency. The study was conducted towards parents who have children attending middle school and high school in Dae-jeon. Official cooperation documents were sent to middle schools and high schools located in Dae-jeon in April, 2013. Surveys were sent by e-mail and a total of 800 replies (excluding those with missing data) collected throughout December 10th to 20th, 2013 were used in the final data analysis. SPSS 23.0 and AMOS 23.0 programs were used for analysis and subject's general characteristics and percentage were analyzed. Pearson's product moment correlation coefficient was used in order to examine the variant's relation. Path model analysis was used to study variant's path and direct and indirect effects of the paths were analyzed as well as the significance. The study's results showed that child life competency and related variants had a high correlation and path model analysis showed that parenting stress, parent efficacy, depression, participation of parent education had a direct and indirect influence on child's life competency. Parenting stress has influence on parent efficacy and depression, but parent education has a different influence on child's life efficacy according to participation. Based on these results, policy suggestions are made throughout family academic perspectives in order to enhance child's life competency.

• The Korean Journal of Applied Statistics
• /
• v.33 no.5
• /
• pp.615-625
• /
• 2020

The document-term frequency matrix is a term extracted from documents in which the group information exists in text mining. In this study, we generated the document-term frequency matrix for document classification according to research field. We applied the traditional term weighting function term frequency-inverse document frequency (TF-IDF) to the generated document-term frequency matrix. In addition, we applied term frequency-inverse gravity moment (TF-IGM). We also generated a document-keyword weighted matrix by extracting keywords to improve the document classification accuracy. Based on the keywords matrix extracted, we classify documents using a deep neural network. In order to find the optimal model in the deep neural network, the accuracy of document classification was verified by changing the number of hidden layers and hidden nodes. Consequently, the model with eight hidden layers showed the highest accuracy and all TF-IGM document classification accuracy (according to parameter changes) were higher than TF-IDF. In addition, the deep neural network was confirmed to have better accuracy than the support vector machine. Therefore, we propose a method to apply TF-IGM and a deep neural network in the document classification.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.3
• /
• pp.60-66
• /
• 2012

This paper aims to constitute a feedback vibration control system using wireless sensor networks and experiment it on a model structure to verify its effectiveness. For the purpose, we set up a feedback vibration control system composed of a wireless input/output(I/O) sensor node based on bluetooth, a home-made shear type MR damper, a shaker which generates a constant size of sine wave, and a simple beam model structure. The vibration control experiment was performed by shaking the 1/4 point of beam with a shaker. At the moment of shaking, we controled the vibration with MR damper which was placed vertically on the center of beam. Simultaneously, by acquiring acceleration response at the 2/4 point of beam, we evaluated the effectiveness of control capability. The control command was set to send a voltage signal to MR damper when the acceleration response, acquired from the wireless I/O sensor node placed at the center of beam, was more than a certain amount. Although the realtime feedback vibration control system constituted in this paper is effective only within a limited command system, it has been proven that the system was able to effectively decrease the vibration of structure by generating a control command aimed for realtime purpose. The system also showed a possibility to be used as a structural response control system adapting a variety of semi-active control algorithm.

• Journal of Navigation and Port Research
• /
• v.36 no.5
• /
• pp.339-347
• /
• 2012

After towing rope connecting a barge to a tug was subdivided into multiple finite elements, then those dynamic models was established using Newton's second law and considering the external force and moment such as tension, drag, Coriolis force, gravity, buoyancy, and impact due to free surface acting on each element. While the previous research on the model of towing rope considered only translation, five-degree-of-freedom equations of motion except roll based on the body-fixed frame were established in this paper. All elements are connected by a spring and a damper, and the stiffness of the spring was set as the equivalent value of the real rope. In order to confirm the established multiple finite element model, various scenarios such as freely falling of towing rope in the air and above the free surface, accelerating of a tug which tows a barge connected by towing rope, and sinusoidal moving of a tug were set up and simulated. As the results, the trajectories of the tug, the barge, and the towing rope showed good tendencies to the ones of real expected situations.

• Journal of Intelligence and Information Systems
• /
• v.25 no.1
• /
• pp.163-177
• /
• 2019

As smartphones are getting widely used, human activity recognition (HAR) tasks for recognizing personal activities of smartphone users with multimodal data have been actively studied recently. The research area is expanding from the recognition of the simple body movement of an individual user to the recognition of low-level behavior and high-level behavior. However, HAR tasks for recognizing interaction behavior with other people, such as whether the user is accompanying or communicating with someone else, have gotten less attention so far. And previous research for recognizing interaction behavior has usually depended on audio, Bluetooth, and Wi-Fi sensors, which are vulnerable to privacy issues and require much time to collect enough data. Whereas physical sensors including accelerometer, magnetic field and gyroscope sensors are less vulnerable to privacy issues and can collect a large amount of data within a short time. In this paper, a method for detecting accompanying status based on deep learning model by only using multimodal physical sensor data, such as an accelerometer, magnetic field and gyroscope, was proposed. The accompanying status was defined as a redefinition of a part of the user interaction behavior, including whether the user is accompanying with an acquaintance at a close distance and the user is actively communicating with the acquaintance. A framework based on convolutional neural networks (CNN) and long short-term memory (LSTM) recurrent networks for classifying accompanying and conversation was proposed. First, a data preprocessing method which consists of time synchronization of multimodal data from different physical sensors, data normalization and sequence data generation was introduced. We applied the nearest interpolation to synchronize the time of collected data from different sensors. Normalization was performed for each x, y, z axis value of the sensor data, and the sequence data was generated according to the sliding window method. Then, the sequence data became the input for CNN, where feature maps representing local dependencies of the original sequence are extracted. The CNN consisted of 3 convolutional layers and did not have a pooling layer to maintain the temporal information of the sequence data. Next, LSTM recurrent networks received the feature maps, learned long-term dependencies from them and extracted features. The LSTM recurrent networks consisted of two layers, each with 128 cells. Finally, the extracted features were used for classification by softmax classifier. The loss function of the model was cross entropy function and the weights of the model were randomly initialized on a normal distribution with an average of 0 and a standard deviation of 0.1. The model was trained using adaptive moment estimation (ADAM) optimization algorithm and the mini batch size was set to 128. We applied dropout to input values of the LSTM recurrent networks to prevent overfitting. The initial learning rate was set to 0.001, and it decreased exponentially by 0.99 at the end of each epoch training. An Android smartphone application was developed and released to collect data. We collected smartphone data for a total of 18 subjects. Using the data, the model classified accompanying and conversation by 98.74% and 98.83% accuracy each. Both the F1 score and accuracy of the model were higher than the F1 score and accuracy of the majority vote classifier, support vector machine, and deep recurrent neural network. In the future research, we will focus on more rigorous multimodal sensor data synchronization methods that minimize the time stamp differences. In addition, we will further study transfer learning method that enables transfer of trained models tailored to the training data to the evaluation data that follows a different distribution. It is expected that a model capable of exhibiting robust recognition performance against changes in data that is not considered in the model learning stage will be obtained.

• Journal of KIISE:Software and Applications
• /
• v.36 no.2
• /
• pp.131-143
• /
• 2009

Based on the fact that a human being walks naturally and stably with consuming a minimum energy, this paper proposes a new method of generating a natural gait of 5-link biped robot like human by analyzing a COG (Center Of Gravity) trajectory of human's gait. In order to generate a natural gait pattern for 5-link biped robot, it considers the COG trajectory measured from human's gait images on the sagittal and frontal plane. Although the human and 5-link biped robot are similar in the side of the kinematical structure, numbers of their DOFs(Degree Of Freedom) are different. Therefore, torques of the human's joints cannot are applied to robot's ones directly. In this paper, the proposed method generates the gait pattern of the 5-link biped robot from the GA algorithm which utilize human's ZMP trajectory and torques of all joints. Since the gait pattern of the 5-link biped robot model is generated from human's ones, the proposed method creates the natural gait pattern of the biped robot that minimizes an energy consumption like human. In the side of visuality and energy efficiency, the superiority of the proposed method have been improved by comparative experiments with a general method that uses a inverse kinematics.