• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.54-59
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• 2020

Coarse aggregate is produced in various ways depending on the location and production method. Currently, the construction industry is in need of a stable supply of coarse aggregate and a way to secure standard quality. The purpose of this study is to examine whether the use of coarse aggregate in 3D printing can help solve this problem. ABS filament was selected for use in 3D printing. CATIA was used for the design of the coarse aggregate, and CUBICON Single Plus was used for the production. Six specimens were produced and cured in water for 28 days. Three of them were made with AE agent, and three were made without it. A compressive strength test confirmed that when the AE agent was used, the compressive strength was greater than the lightweight concrete design criterion specified in the concrete standard specification. This suggests that coarse aggregate produced by a 3D printer may be used for lightweight concrete. A mass production system using this method could help to solve the problems facing the construction industry, such as stable supply and demand for coarse aggregate and securing standard quality.

• KIISE Transactions on Computing Practices
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• v.21 no.2
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• pp.154-159
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• 2015

Over the past few years, user needs in the smartphone application market have been shifted from diversity toward intelligence. Here, we propose a novel cognitive agent that plans the daily routines of users using the lifelog data collected by the smart phones of individuals. The proposed method first employs DPGMM (Dirichlet Process Gaussian Mixture Model) to automatically extract the users' POI (Point of Interest) from the lifelog data. After extraction, the POI and other meaningful features such as GPS, the user's activity label extracted from the log data is then used to learn the patterns of the user's daily routine by POMDP (Partially Observable Markov Decision Process). To determine the significant patterns within the user's time dependent patterns, collaboration was made with the SNS application Foursquare to record the locations visited by the user and the activities that the user had performed. The method was evaluated by predicting the daily routine of seven users with 3300 feedback data. Experimental results showed that daily routine scheduling can be established after seven days of lifelogged data and feedback data have been collected, demonstrating the potential of the new method of place-time-activity coupled daily routine planning systems in the intelligence application market.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2708-2712
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• 2010

Amines, ammonia or 3-methoxypropylamine (MPA), are used to maintain the optimized pH for the prevention of corrosion in the secondary side of Pressurized Water Reactors (PWRs). They are differently dissociated as a function of temperature which is not same in each location of the water-steam cycle. pH at the operation temperature depends on temperature of fluid and equilibrium constants of water and amines. Thus, every amine provides the different pH in the entire secondary side so that pH is not only the sufficient parameter in corrosion control. The secondary parameter, i.e., buffer intensity, is the ability to maintain a stable pH when $H^+$ are added or removed due to the ingress of impurities or the reaction of corrosion. The buffer intensity is necessary to provide the selection criteria for the best pH control agent for secondary side and the basic understanding of the reason why the flow-accelerated corrosion(FAC) rate may demonstrate the bell-shape curve over temperature. The buffer intensities of ammonia and MPA were reviewed over the entire operation temperature of PWRs. The sufficient buffer intensity is provided for the inhibition of corrosion by ammonia in low temperature $(25{\sim}100^{\circ}C)$ and by DMA in high temperature $(150{\sim}250^{\circ}C)$. In terms of buffer intensity, i) the best pH control agent is an amine with $pK_a(T)$ range of pH(T)- $1{\leq}pK_a(T){\leq}pH(T)$ + 0.5 and ii) the amine solution should have sufficient buffer intensity, ${\beta}$ to inhibit corrosion, and iii) FAC rate may be maximum at the temperature, where ${\beta}_B/{\beta}$ ratio is lowest.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.42-52
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• 2002

Information extraction(IE) is a process of recognizing and fetching particular information fragments from a document. In previous work, most IE systems generate the extraction rules called the wrappers manually, and although this manual wrapper generation may achieve more correct extraction, it reveals some problems in flexibility, extensibility, and efficiency. Some other researches that employ automatic ways of generating wrappers are also experiencing difficulties in acquiring and representing useful domain knowledge and in coping with the structural heterogeneity among different information sources, and as a result, the real-world information sources with complex document structures could not be correctly analyzed. In order to resolve these problems, this paper presents an agent-based information extraction system named XTROS that exploits the domain knowledge to learn from documents in a semi-structured information source. This system generates a wrapper for each information source automatically and performs information extraction and information integration by applying this wrapper to the corresponding source. In XTROS, both the domain knowledge and the wrapper are represented as XML-type documents. The wrapper generation algorithm first recognizes the meaning of each logical line of a sample document by using the domain knowledge, and then finds the most frequent pattern from the sequence of semantic representations of the logical lines. Eventually, the location and the structure of this pattern represented by an XML document becomes the wrapper. By testing XTROS on several real-estate information sites, we claim that it creates the correct wrappers for most Web sources and consequently facilitates effective information extraction and integration for heterogeneous and complex information sources.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.23-39
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• 2005

As developing satellite communication, the tracking range of the moving objects which move in local area is expanded to the whole world. However previous logistics management system is able to monitor freight which transporting in local area using mobile communication system. In this paper, we propose the reefer container management system that manages the location information and other related information such as temperature, humidity of container using the satellite system. The proposed system consists of three parts; data collector, satellite communication manager, reefer container information manager. And the proposed system uses the moving object index for managing the trajectory of container and tracing the location of container or vessel that is transporting the container, and supports various services such as reefer container and vessel tracking, container control and container statistics to logistic companies like shipper and forwarding agent. And the system can be increasing the quality of container transportation service to the shipper, and it makes the efficient management of reefer container to the shipping company.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.1-7
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• 2008

Today, Korean medical community faces rapid changes in medical environment due to opening of medical market, more emphasis on making profit and introduction of private medical insurance. Therefore, it is apparent that around, major university hospitals, efforts are being made to adapt to such changes by establishing mid to long range strategic plans. We want to keep pace with changing times and diverse demand of patients by introducing state of the art system, utilizing Ubiquitous technologies for improvements. In doing so, we want to distinguish our hospital services from others. However, Hospital Information System that integrates ubiquitous technologies are introduced in limited basis due to problems like standardization and limits on medical use etc. Particularly, problems like absence of tag design suitable for medical environment, compatibility and extension issue with RFID system need to be addressed on application of RFID technologies. In order to solve such problems, this paper implemented RFID tag system, RFID-SIP UA program, location tracking program. This paper provides a comprehensive basic review of RFID and SIP model suggests the evolution direction of further advanced RFID application service. The design of RFID-SIP application offers advance RFID system with drawback and reduction search time of medical object. so there is a improvement of hospital information system in ubiquitous environment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.381-389
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• 2009

Confined spaces are inherently dangerous workplace and many fatal and nonfatal accidents have been reported. Even though these accidents occur in various kinds of confined spaces, there has rarely been reported on the health hazard agent, i.e., the types of gases and their concentration ranges. Therefore in this study, we evaluated several toxic and asphyxiating gas concentrations in various confined spaces. We surveyed 57 manholes, 3 sewage treatment plants, 2 yellow radish manufacturing companies and 7 barges to measure the concentrations of oxygen($O_2$), hydrogen sulfide($H_2S$), carbon monoxide(CO), ammonia($NH_3$). Lower Explosion Limits(LEL) and Volatile Organic Compounds (VOCs). Those four types of confined spaces occupies 56% of accidents during last 9 years in Korea. In 57 manholes, the concentration varied according to the types of manholes; rainfall and sewage, and by location; residential and industrial areas. Sewage manhole in industrial area was evaluated as the most hazardous than other types of manhole like rainfall manholes, residential sewage manholes. The highest $H_2S$ concentration and the lowest $O_2$ concentration at sewage manhole in industrial area were 300 ppm, 8.7% respectively. In 3 sewage treatment plants, $H_2S$ and $NH_3$ concentrations were reached up to the 500 ppm and 200 ppm respectively. Two yellow radish manufacturing companies showed the concentrations of 316 ppm, 505.2 ppm, 90 ppm and 15.7% for $H_2S$, CO, VOCs and $O_2$, respectively. Seven barges showed 15.9%~20.9% oxygen concentration. Gas species and concentration ranges varied by the types and location of confined spaces; CO, $H_2S$, $O_2$ could be hazardous in manhole, especially manhole connected to sewage plants. CO, $H_2S$, LEL, $O_2$, $NH_3$ should be controlled in sludge silo and sluge pumping confined spaces in sewage treatment plant. The activity of lifting out radish from the storage tank was evaluated more hazardous rather than the other activities in yellow radish manufacturing industry. The employers must conduct the survey to identify all possible confined spaces in their local workplace prior to performing the tasks. At the national level to reduce the accidents in the confined spaces, we suggest that systemic approach and active education program including possible hazards, standard operation procedures, ventilation plan, and personal protective equipment in confined spaces should be implemented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.546-554
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• 2019

Typically, closed-circuit television (CCTV) monitoring is mainly used for post-processes (i.e. to provide evidence after an incident has occurred), but by using a streaming video feed, machine-based learning, and advanced image recognition techniques, current technology can be extended to respond to crimes or reports of missing persons in real time. The multi-CCTV cooperation technique developed in this study is a program model that delivers similarity information about a suspect (or moving object) extracted via CCTV at one location and sent to a monitoring agent to track the selected suspect or object when he, she, or it moves out of range to another CCTV camera. To improve the operating efficiency of local government CCTV control centers, we describe here the partial automation of a CCTV control system that currently relies upon monitoring by human agents. We envisage an integrated crime prevention service, which incorporates the cooperative CCTV network suggested in this study and that can easily be experienced by citizens in ways such as determining a precise individual location in real time and providing a crime prevention service linked to smartphones and/or crime prevention/safety information.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.370-381
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• 2005

Mobile IP provides an efficient and scalable mechanism for host mobility within the Internet. Using Mobile If, mobile nodes may change their point of attachment to the Internet without changing their If address. However, it would result in a high signaling cost. To reduce the signaling cost, we factor in the fact that mobile users will not be actively communicating much of the time. In fact, there Is no necessity to send a binding update message to the home agent when an mobile node does not communicates with others while moving. From this point of view, we propose a lazy update strategy for minimizing signaling cost using the forwarding pointer in hierarchical Mobile IPv6. In our proposal, binding updates are sent only when a mobile node is in a busy mode. If an mobile node is in a dormant mode, binding update messages are delayed until busy mode using the forwarding pointer. As a result, our proposal can reduce the total signaling cost by eliminating unnecessary binding update messages when a mobile node Is in a dormant mode. In addition to, our proposal reduces unnecessary location update cost resulting from ping-pong effect under mobile node's dormant mode. Analysis results using the discrete analytic model presented in this paper shows that our proposal can has superior performance than hierarchical Mobile nv6 when the call-to-mobility ratio is low and the length of the forwarding pointer chain K is low.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.394-404
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• 2006

Statement of problem: A conventional 3-unit fixed partial denture design with a pontic between two retainers is the most commonly used. However in cases where the mental nerve is in close proximity to the second premolar, a cantilever design can be considered. As such, logical and scientific evidence is lacking for the number and position of implants to be placed for partially edentulous patients, and no clear-cut set of treatment principles currently exist. Purpose : The purpose of this study was to evaluate prognosis of implant-supported fixed partial dentures and to compare changes in bone level which may rise due to the different factors. Material and method : The present study examined radiographical marginal bone loss in patients treated with implant-supported fixed partial dentures (87 prostheses supported by 227 implants) and evaluated the influence of the span of the pontic, type of the opposing dentition. Clinical complications were studied using a retrospective method. Within the limitation of this study. the following result were drawn Result, 1. Seven of a total of 227 implants restored with fixed prostheses failed, resulting in a 96.9% success rate. 2. Complications encountered during recall appointments included dissolution of temporary luting agent (17 cases), porcelain fracture (8 cases), loosened screws (5 cases), gingival recession (4 cases), and gingival enlargement (1 case). 3. Marginal bone loss, 1 year after prosthesis placement, was significant(P<0.05) in the group that underwent bone grafting, however no difference in annual resorption rate was observed afterwards. 4. Marginal bono loss, 1 year post-placement, was greater in cantilever-type prostheses than in centric pontic protheses (P<0.05). 5. Marginal bone loss was more pronounced in posterior regions compared to anterior regions (P<0.05). 6. The degree of marginal bone loss was proportional to the length of the pontic (P<0.05). Conclusion: The success rate of implant-supported fixed partial dentures, including marginal bone loss, was satisfactory in the present study. Factors influencing marginal bone loss included whether bone graft was performed, location of the pontic (s), location of the surgical area in the arch pontic span. Long-term evaluation is necessary for implant-supported fixed partial dentures, as are further studies on the relationship between functional load and the number of implants to be placed.