• KIEAE Journal
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• v.17 no.5
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• pp.69-76
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• 2017

Purpose: This study aimed at developing an Artificial Neural Network (ANN) model for predicting the amount of cooling energy consumption of the variable refrigerant flow (VRF) cooling system by the different set-points of the control variables, such as supply air temperature of air handling unit (AHU), condenser fluid temperature, condenser fluid pressure, and refrigerant evaporation temperature. Applying the predicted results for the different set-points, the control algorithm, which embedded the ANN model, will determine the most energy efficient control strategy. Method: The ANN model was developed and tested its prediction accuracy by using matrix laboratory (MATLAB) and its neural network toolbox. The field data sets were collected for the model training and performance evaluation. For completing the prediction model, three major steps were conducted - i) initial model development including input variable selection, ii) model optimization, and iii) performance evaluation. Result: Eight meaningful input variables were selected in the initial model development such as outdoor temperature, outdoor humidity, indoor temperature, cooling load of the previous cycle, supply air temperature of AHU, condenser fluid temperature, condenser fluid pressure, and refrigerant evaporation temperature. The initial model was optimized to have 2 hidden layers with 15 hidden neurons each, 0.3 learning rate, and 0.3 momentum. The optimized model proved its prediction accuracy with stable prediction results.

• Journal of The Korean Association of Information Education
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• v.9 no.3
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• pp.453-462
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• 2005

Recently, due to technical improvements of storage devices and networks, the amount of data increase rapidly. In addition, it is required to find the knowledge embedded in a data stream as fast as possible. Huge data in a data stream are created continuously and changed fast. Various algorithms for finding frequent itemsets in a data stream are actively proposed. Current researches do not offer appropriate method to find frequent itemsets in which flow of time is reflected but provide only frequent items using total aggregation values. In this paper we proposes a novel algorithm for finding the relative frequent itemsets according to the time in a data stream. We also propose the method to save frequent items and sub-frequent items in order to take limited memory into account and the method to update time variant frequent items. The performance of the proposed method is analyzed through a series of experiments. The proposed method can search both frequent itemsets and relative frequent itemsets only using the action patterns of the students at each time slot. Thus, our method can enhance the effectiveness of learning and make the best plan for individual learning.

• The Journal of Sustainable Design and Educational Environment Research
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• v.10 no.2
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• pp.61-72
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• 2011

The purpose of this study is to carry out the research of the satisfaction level of consumers (students and teachers) and managerial characteristics for model classes of the subject classroom system and to draw the effective plan of the system. The conclusions are as follows First, the biggest advantage of the system is to fulfill the educational goal according to an individual level and ability of each student while the biggest disadvantage is the inconvenience of students to change their classrooms for each specific class. Second, it is necessary to rearrange the classrooms according to the applied subjects from the aspect of curriculum management since the time frame is not convenient for recess. English and mathematics are required preferentially as applied subjects, however Korean (as a national language) and science are needed to be taught with level-differentiated classes, too. The ideal size of classes is most likely 20-25 students according to the result of research. Lastly, the space of environment is another requirement to secure smooth flow of students' movements and extra space for technical devices used for information research. The above analysis indicates the necessity of supplementation in space planning for further implementation of subject classroom system in secondary school.

• Journal of National Security and Military Science
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• s.3
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• pp.197-242
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• 2005

Active catalog is a kind of digital content that enables consumers to test the functions and features of products from their PCs as if they were using it in real life, by simulating the actions and responses of the product. This new type of interactive digital content can be used extensively to make sales personnel training manuals, sales tools, user manuals and user trouble shooting documents. With active catalogs, companies will be able to compare different designs, show actions according to different functions, and evaluate user reaction to new products without having to produce a single physical prototype or mock-up. At the same time, consumers will be able to understand and 'operate' the product and make well-informed purchase decisions. In this paper, we present a visual event-driven modeling tool, PlayMo, for creating active catalogs, analyze the advantages of using PlayMo, describe the event-driven method used by PlayMo and also introduce two enhanced characteristics of the Event Flow Chart with which the events in PlayMo are structured. Interactive digital content by using the PlayMo3D makes easy, simple and effective design for e-learning, e-catalogue, e-marketing/sales, e-prototyping, customer support, etc. Through its application-ready 3D function visualization solution, engineers and designers can rapidly turn a CAD design model into a 3D interactive virtual product, and the effective function prototyping job can be also completed within a minute.

• Journal of Korean Academy of Nursing
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• v.24 no.2
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• pp.206-215
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• 1994

Intuition is an abstract concept which is most often thought of as a nonrational, nonscientific mode of thought. However, since there are so many amorphous definitions of intuition that it seems important to clarify the meaning of this concept. Therefore, this study use the process of Walker & Avant’s concept analysis to define of the concept of intuition Attributes of intuition were defined as 1) Knowledge of truth that is difficult to explicate ; 2) A type of immediate knowing ; 3) Knowlwdge without reasining analysis ; 4) Knowledge that is attained based on virtue character which integrates all matter and is not attained through individual experience. Antecedents of intuition consists of 1) as ground for knowledge or truth that is not availables to trace through the analytic procedures ; & 2) the flow of Ki which unites human beings and the universe. Consequences of intuition events or incidents occuring as a result of the concept consist of verification of the truth though analytic procedures and application of knowledge in both theoretical and practical ways. To develop intuitive ability, as an educator should not only make studies in recognizine, analysing and teaching concepts related to logical, rational decision making but should also recognize and teach concepts related to intuitive components of making decisions in clinical practice and classroom learning as well.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.74-81
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• 2024

In the near future, autonomous ships, ships controlled by shore remote control centers, and ships operated by navigators will coexist and operate the sea together. In the advent of this situation, a method is required to evaluate the safety of the maritime traffic environment. Therefore, in this study, a plan to evaluate the safety of navigation through ship control simulation was proposed in a maritime environment, where ships directly controlled by navigators and autonomous ships coexisted, using autonomous operation technology. Own ship was designed to have autonomous operational functions by learning the MMG model based on the six-DOF motion with the PPO algorithm, an in-depth reinforcement learning technique. The target ship constructed maritime traffic modeling data based on the maritime traffic data of the sea area to be evaluated and designed autonomous operational functions to be implemented in a simulation space. A numerical model was established by collecting date on tide, wave, current, and wind from the maritime meteorological database. A maritime meteorology model was created based on this and designed to reproduce maritime meteorology on the simulator. Finally, the safety evaluation proposed a system that enabled the risk of collision through vessel traffic flow simulation in ship control simulation while maintaining the existing evaluation method.

• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.97-104
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• 1998

In order to advise how to solve the problems and suggest on the mechanization of beef farm, the facilities and equipment for feeding and supplying water to the animals and transporting manure, and farm machineries of sixty-seven beef cattle farms in western Chungnam Province were surveyed. The results are as follows; 1. The proportions of number of heads per farm for above 70, 50∼70, 30∼50, 10∼30 and below 10 heads were 26, 18, 29, 13 and 13, respectively. The farms with the annual income more than 30 million won are consisted of 67.6% of the farms surveyed which showed to be higher than national average. 2. Only 19% of farms had automatic feeding system. Water was supplied by water cup(45%), opening and shutting water tab(27.6%) and bucket. 3. Cattle manure was transported by manpower (46%) by loader (34%) and by gravitational flow (14%). Most of manure(97%) was composted after treatment of drying or piling up outside. 4. More instruction and education were required because of the insufficient routine checking and fixing for farming machines, and unsystematic education for learning skills. 5. 65% of farms felt unsatisfied about after service(A/S) for their machinery. The main reason why the farmers were not satisfied was that it took too much time to be repaired. 6. When the farms purchased facilities, equipment and machinery, they did not analyze economic value of them and keep a diary. To make effective use of machines, the most available model for purchasing and managing of machines must be developed and applied to various scales of management.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.2
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• pp.133-146
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• 2023

Traffic states in urban areas are essential to implement effective traffic operation and traffic control. However, installing traffic sensors on numerous road sections is extremely expensive. Accordingly, estimating the traffic state using a vehicle-mounted camera, which shows a high penetration rate, is a more effective solution. However, the previously proposed methodology using object tracking or optical flow has a high computational cost and requires consecutive frames to obtain traffic states. Accordingly, we propose a method to detect vehicles and lanes by object detection networks and set the region between lanes as a region of interest to estimate the traffic density of the corresponding area. The proposed method only uses less computationally expensive object detection models and can estimate traffic states from sampled frames rather than consecutive frames. In addition, the traffic density estimation accuracy was over 90% on the black box videos collected from two buses having different characteristics.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.373-382
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• 2023

The task of sorting and excluding blemished apples and others that lack commercial appeal is currently performed manually by human eye sorting, which not only causes musculoskeletal disorders in workers but also requires a significant amount of time and labor. In this study, an automated apple-sorting machine was developed to prevent musculoskeletal disorders in apple production workers and to streamline the process of sorting blemished and non-marketable apples from the better quality fruit. The apple-sorting machine is composed of an arm-rest, a main body, and a height-adjustable part, and uses object detection through a machine learning technology called 'You Only Look Once (YOLO)' to sort the apples. The machine was initially trained using apple image data, RoboFlow, and Google Colab, and the resulting images were analyzed using Jetson Nano. An algorithm was developed to link the Jetson Nano outputs and the conveyor belt to classify the analyzed apple images. This apple-sorting machine can immediately sort and exclude apples with surface defects, thereby reducing the time needed to sort the fruit and, accordingly, achieving cuts in labor costs. Furthermore, the apple-sorting machine can produce uniform quality sorting with a high level of accuracy compared with the subjective judgment of manual sorting by eye. This is expected to improve the productivity of apple growing operations and increase profitability.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.372-387
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• 2012

This study aims to identify unique small group norms and their influence on the process of constructing a scientific model. We developed instructional materials for the construction of a model of blood flow in the heart and conducted research on eighth-grade students from one middle school. We randomly selected 10 small groups, and videotaped and recorded their dialogues and behaviors. The data was categorized according to the types of interaction and then analyzed to investigate the characteristics of group norms and models in one or two representative groups for each type. The results show that the types of interaction, the quality of the group models, and the group norms were different in each group. Even though one teacher guided students through the same task in the inquiry context, each group revealed different patterns of discourse and behavior, which were based on norms of cognitive responsibility, the need for justification, participation, and membership. With the exception of one group, there was little cognitive responsibility and justification for students' opinions. Ultimately, these norms influenced the model construction of small groups. A group that forms norms to encourage the active participation and justify members' opinions with cognitive responsibility was encouraged to do inferential thinking and construct a group model close to the target model. This study has instructional implications for the establishment of a classroom environment that facilitates learning through small group activities.