• Journal of the Korean Chemical Society
• /
• v.67 no.5
• /
• pp.378-392
• /
• 2023

The purpose of this study is to analyze the pre-service chemistry teachers' cognition of the nature of model in process of designing and developing models using technology. For this purpose, 19 pre-service chemistry teachers' in the 3rd grade of a education college located in the central region observe experimental phenomena related to Boyle's law presented in the 7th grade science textbook and researchers required the design and development of a model related to the observed experimental results using technology. Based on previous studies, the nature of model were classified into two aspect: 'Representational aspect' and 'Explanatory aspect'. The 'Representational aspect' was classified into 'Representation', 'Abstraction', and 'Simplification', and the 'Explanatory aspect' was classified into 'Analysis', 'Interpretation', 'Reasoning', 'Explanation', and 'Quantification'. The pre-service chemistry teachers' cognition were analyzed by the classification. As a result of the study, the 'Representation' of the 'expressive aspect' was uniformized in the form of space that changes in volume, and the pressure was expressed as the Brightness inside the cylinder or frequency of color change of particles for 'Abstraction'. In the case of 'Simplification', the particle collision was expressed as a perfectly elastic collision, but there was a group that could not simply indicate the type of particle. In the 'Explanatory aspect', in the case of 'Analysis', volume was classified as a manipulated variable, and in the case of 'Interpretation', most groups analyzed the change in pressure through the collision of gas particles. However, the cognition involved in 'Reasoning' was not observed much. In the case of 'Explanation', there were groups that did not succeed in explanation because the area where the particles collided was not set or incorrectly set, and in the case of 'Quantification', there was a group that formulated the number of collisions per unit time, and on the contrary, there was a group that could not quantify the number of collisions because they could not be expressed in numbers.

• The KIPS Transactions:PartD
• /
• v.10D no.7
• /
• pp.1103-1114
• /
• 2003

Currently, one of the most critical issues in developing the service support system for various spatio-temporal applications is the discoverying of meaningful knowledge from the large volume of moving object data. This sort of knowledge refers to the spatiotemporal moving pattern. To discovery such knowledge, various relationships between moving objects such as temporal, spatial and spatiotemporal topological relationships needs to be considered in knowledge discovery. In this paper, we proposed an efficient method, MPMine, for discoverying spatiotemporal moving patterns. The method not only has considered both temporal constraint and spatial constrain but also performs the spatial generalization using a spatial topological operation, contain(). Different from the previous temporal pattern methods, the proposed method is able to save the search space by using the location summarization and generalization of the moving object data. Therefore, Efficient discoverying of the useful moving patterns is possible.

• Journal of KIISE
• /
• v.45 no.3
• /
• pp.294-302
• /
• 2018

With the emergence of the new service industry due to the development of information and communication technology, cyber space risks such as personal information infringement and industrial confidentiality leakage have diversified, and the security problem has emerged as a critical issue. In this paper, we propose a behavior-based anomaly detection method that is suitable for real-time and large-volume data analysis technology. We show that the proposed detection method is superior to existing signature security countermeasures that are based on large-capacity user log data according to in-company personal information abuse and internal information leakage. As the proposed behavior-based anomaly detection method requires a technique for processing large amounts of data, a real-time search engine is used, called Elasticsearch, which is based on an inverted index. In addition, statistical based frequency analysis and preprocessing were performed for data analysis, and the DBSCAN algorithm, which is a density based clustering method, was applied to classify abnormal data with an example for easy analysis through visualization. Unlike the existing anomaly detection system, the proposed behavior-based anomaly detection technique is promising as it enables anomaly detection analysis without the need to set the threshold value separately, and was proposed from a statistical perspective.

• Korean Institute of Interior Design Journal
• /
• v.19 no.1
• /
• pp.180-189
• /
• 2010

Since collective houses are started to be supplied, the housing market has been transformed from supplier to demander oriented, and various type with same area of unit households have been deigned and started to be distributed. It can be expected that such transfer phenomenon would be continuously sped-up, and unit household will be more subdivided and varied. Thus, we analysed and studied the planes with subject of unit households in national housing scale ($85m^2$) that is treated as supply standard and has biggest volume in construction by Korean housing corporation. The analysing method is investigating the area of each room within unit household, calculating their minimum, maximum, and average values, studying the efficiency of unit household plane according to the structure of each room by comparative analysis these values, and analysing changing matter by investigating any change of each room area. The analysing results of which are followings. At first, number of BAY on face is increasing. Second, allocation of each room has been vary. Third, area ratio among bedroom1, livingroom, diningroom/kitchen become similar. Fourth, the area of diningroom/kitchen become somewhat bigger. Fifth, the space for passage way is efficiently allocated. Sixth, service area is reduced, Seventh, stereotyped phenomenon Is appeared. Based on many studies so far, any improvements of unit householder in national housing scale are followings. First, in terms of forming style, unit householder in national housing scale is unfolded in various way though, the form of each room is not more than typical style. Second, it shows stereotyped phenomenon. Especially, bathroom 1, 2 show stereotyped feature in terms of their type and area across entire research years, also LDK allocation method is stereotyped, as well as stereotyped trend in bedroom 2, 3, allocation for 4 BAY type.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5D
• /
• pp.579-585
• /
• 2009

In spite of the proven effectiveness of ramp metering system, it has not been successfully implemented in Korean setting. The purpose of this paper is to select target locations to introduce ramp metering into the Korean expressway system. For this, domestic standards to introduce ramp metering have been presented after reviewing those of the US. The major criteria are level of service (LOS), the existence of detour route, space for queue build-up and opened ramp. 15 different locations were selected and AHP has been used to make priority among them. Intuitively, the result of priority was in accordance with the congestion and traffic volume. The core results identified in this paper is expected to be used in different cities and expressway networks elsewhere.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.19 no.6
• /
• pp.845-856
• /
• 2017

In the long railway tunnel, in order to secure safety in case of fire, it is required a emergency station. However, there is no standard or research results on smoke exhaust method and exhaust flow rate in emergency station, so it is necessary to study the smoke exhaust system for emergency station. In this study, we are created a numerical analysis model for emergency station where the evacuation cross passage connected to the service tunnel or the relative tunnel was installed at regular intervals (40 m intervals). And the fire analysis are carried out by varying the fire intensity (15, 30MW), the smoke exhaust method (only air supply, forced air supply and exhaust, forced air exhaust only), and the air flow rate (7, 14, $40m^3/s$). From the results of fire analysis, temperature and CO concentration are analyzed and ASET based on the limit temperature are compared at various condition. As a result, in the case with fire intensity of 15 MW, it is shown that a sufficiently safe evacuation environment can be ensured by applying forced air supply and exhaust method or forced air exhaust only method when the air flow rate is $7m^3/s$ above. In case of fire intensity of 30 MW, it is impossible to maintain the safety evacuation environment for more than 900 seconds when the exhaust air volume is below $14m^3/s$. And when the air flow rate is $40m^3/s$, the exhaust port is disposed at the side portion of the upper duct, which is most advantageous for securing the temperature-based safety.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.8
• /
• pp.85-92
• /
• 2016

Mobile cloud computing (MCC) is not just extensions of cloud concepts into mobile environments, but the service technologies that all mobile devices including smartphone can use the desired services by using cloud technology without the constraints of time and space. Currently, a lot of works on mobile cloud computing have been actively researching, whereas user interfaces are not so much researched. The main features and contributions of this paper are as follows. First, develop UI considering UX that is different from conventional interfaces supported by SPICE. Second, combine two button interface into one button interface when keyboard is used in mobile cloud computing clients. Third, develop a mouse interface suitable for mobile cloud computing clients. Fourth, in mobile cloud computing client, solve a problem that the selection of button/files/folder has at the corner. Finally, in mobile cloud computing clients we change mouse scroll mapping functions from volume button to scroll interface in touch-screen. The results of performance evaluation shows that users can input easily with the increased and fixed mouse interface. Since shortcut keys instead of the complex button keys of keyboard are provided, the input with 3-6 steps is reduced into 1 step, which can simply support complex keys and mouse input for users.

• Journal of Korean Society for Atmospheric Environment
• /
• v.26 no.5
• /
• pp.543-553
• /
• 2010

Almost five million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan. As the subway system is typically a closed environment, indoor air pollution problems frequently occurs and passengers complain of mal-health impact. Especially $PM_{10}$ is well known as one of the major pollutants in subway indoor environments. The purpose of this study was to compare the indoor air quality in terms of $PM_{10}$ and to quantitatively compare its source contributions in a Seoul subway platform before and after installing platform screen doors (PSD). $PM_{10}$ samples were collected on the J station platform of Subway Line 7 in Seoul metropolitan area from Jun. 12, 2008 to Jan. 12, 2009. The samples collected on membrane filters using $PM_{10}$ mini-volume portable samplers were then analyzed for trace metals and soluble ions. A total of 18 chemical species (Ba, Mn, Cr, Cd, Si, Fe, Ni, Al, Cu, Pb, Ti, $Na^+$, $NH_4^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, and ${SO_4}^{2-}$) were analyzed by using an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the source of particulate matters. $PM_{10}$ for the station was characterized by three sources such as ferrous related source, soil and road dust related source, and fine secondary aerosol source. After installing PSD, the average $PM_{10}$ concentration was decreased by 20.5% during the study periods. Especially the contribution of the ferrous related source emitted during train service in a tunnel route was decreased from 59.1% to 43.8% since both platform and tunnel areas were completely blocked by screen doors. However, the contribution of the fine secondary aerosol source emitted from various outside combustion activities was increased from 14.8% to 29.9% presumably due to ill-managed ventilation system and confined platform space.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.11
• /
• pp.797-809
• /
• 2006

To support the QoS streams for large scale clients, the internal resources of VOD servers should be utilized based on the characteristics of the streaming media service. Among the various resources in the server, the main memory is used for the buffer space to the media data loaded from the disks and the buffer hit ratio has a great impact upon the server performance. However, if the buffer data with high hit ratio are replaced for the new media data as a result of the number of clients and the required movie titles are increased, the negative impact on the scalability of server performance is occurred. To address this problem, the buffer replacement policy considers the intrinsic characteristics of the streaming media such as the sequential access to large volume data and the highly disproportionate preference to specific movies. In this paper, the preference-based segment buffer replacement policy is proposed in the cluster-based VOD server to exploit the characteristics of the streaming media. Since the proposed method reflects both the temporal locality by the clients' preference and the spatial locality by the sequential access to media data, the buffer hit ratio would be improved as compared to the existing buffer replacement policy. The enhanced buffer hit ratio causes the fact that the performance scalability of the cluster-based VOD server is linearly improved as the number of cluster nodes is increased.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.4
• /
• pp.76-91
• /
• 2017

The Area of a domestic railway station is designed based on the 4-step traffic demand forecasting model with the average daily passenger count as one of its parameter. However, nowadays, due to increasing rate of railway station's function, the non-passengers are increasing. In order to consider those non-passengers who aren't using trains, assumed volume are added to the average daily passenger count of station to estimate the area, but the criteria being applied has no concrete basis. Therefore, this study aimed to recalculate the increasing non-passenger rate based on actual survey data of station users in any type of railway station to obtain the optimum area. Subsequently, the the design area was performed through pedestrian simulation. According to the result of the simulation, it was found that the total space of the exciting railway stations can be reduced up to 45% and will still satisfy the level of service(LOS) requirement.