• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.469-473
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• 2009

We present high-voltage liquid-electrolyte microbatteries, inspired from the high-voltage generation mechanism of electric eels using serially connected multiple-cell arrays. In the microbatteries, we purge air into the electrolyte filled in a channel layer to isolate serially connected multiple cell arrays using three surface-tension valves (cell-front, outlet, and cell-end valves). Compared to the previous multi-cell stack or interconnection, present microbatteries provide a reduced multi-cell charging time. We have designed and characterized four different prototypes C1, C10, C20, and C40 having 1, 10, 20, and 40 cells, respectively. In the experimental study, the threshold pressures of cell-front, outlet, and cell-end valves were measured as $460{\pm}47$, $1,000{\pm}53$, and $2,800{\pm}170$ Pa, respectively. The average charging time for C40 was measured as $26.8{\pm}4.9$ seconds where the electrolyte and air flow-rates are 100 and $10{\mu}l/min$, respectively. Microbatteries showed the maximum voltage of 12 V (C40), the maximum power density of $110{\mu}W/cm^2$ (C40), and the maximum power capacity of $2.1{\mu}Ah/cm^2$ (C40). We also proposed a tapered-channel to remove the reaction gas from the cell chamber using a surface tension effect. The present microbatteries are applicable to high-voltage portable power devices.

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

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.2
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• pp.153-159
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• 2016

Rivers refer to either natural or artificial structures whose primary functions are flood control and water conservation. Due to recent localized torrential downpours led by climate change, large amounts of eroded soil have been carried away, forming deposits downstream, which in turn degrades the capacity to fulfill these functions. To manage rivers more effectively, we need data on riverbed erosion and deposition. However, environmental factors make it challenging to take measurements in rivers, and data errors tend to prevent researchers from grasping the current state of erosions and deposits. In this context, the aim of the present study is to provide basic data required for river management. To this end, the author made annual measurements with a Real-time Kinematic-Global Positioning System (RTK-GPS) and a total station in Pats Cabin Canyon, Oregon, United States, and also prepared thematic maps of erosion and deposition thickness as well as water depth profiles based on a GIS spatial analysis. Furthermore, the author statistically analyzed the accuracy of three dimensional (3D) measurement points and only used the data that falls within two standard deviations (i.e. ±2σ). In addition, the author determined a threshold for a DEM of Difference (DoD) by installing measurement points in the rivers and taking measurements, and then estimated erosion and deposition thickness within a confidence interval of ±0.1m. Based on the results, the author established reliable data on river depth profiles and thematic maps of erosion and deposition thickness using pre-determined work flows. It is anticipated that the riverbed data can be utilized for effective river management.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.129-137
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• 2017

PURPOSES : The purpose of this study is to develop bridge deck concrete materials based on ordinary Portland cement concrete, and to evaluate the applicability of the developed materials through material properties tests. METHODS : For field implementation, raw material (cement, fine aggregate, and coarse aggregate) properties, fresh concrete properties (slump and air content), strength (compressive, flexural and bond strength) gain, and durability (freeze-thaw resistance, scaling resistance, and rapid chloride penetrating resistance) performance were evaluated in the laboratory. RESULTS : For the selected binder content of $410kg/m^3$, W/B = 0.42, and S/a = 0.48, the following material performance results were obtained. Considering the capacity of the deck finisher, a minimum slump of 150 mm was required. At least 6 % of air content was obtained to resist freeze-thaw damage. In terms of strength, 51.28 MPa of compressive strength, 7.41 MPa of flexural strength, and 2.56 MPa of bond strength at 28 days after construction were obtained. A total of 94.9 % of the relative dynamic modulus of elasticity after 300 cycles of freeze-thaw resistance testing and $0.0056kg/m^2$ of weight loss in a scaling resistance test were measured. However, in a chloride ion penetration resistance test, the result of 3,356 Coulomb, which exceeds the threshold value of the standard specification (1000 Coulomb at 56 days) was observed. CONCLUSIONS : Instead of using high-performance modified bridge deck materials such as latex or silica fume, we developed an optimum mix design based on ordinary Portland cement concrete. A test construction was carried out at ramp bridge B (bridge length = 111 m) in Gim Jai City. Immediately after the concrete was poured, the curing compound was applied, and then wet mat curing was applied for 28 days. Considering the fact that cracks did not occur during the monitoring period, the applicability of the developed material is considered to be high.

• Radiation Oncology Journal
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• v.31 no.1
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• pp.34-40
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• 2013

Purpose: To evaluate the predictive factors of radiation pneumonitis (RP) and associated changes in pulmonary function after definitive concurrent chemoradiotherapy (CCRT) in patients with non-small cell lung cancer (NSCLC). Materials and Methods: Medical records of 60 patients with NSCLC who received definitive CCRT were retrospectively reviewed. Dose volumetric (DV) parameters, clinical factors, and pulmonary function test (PFT) data were analyzed. RP was graded according to the CTCAE ver. 4.0. Percentage of lung volume that received a dose of threshold (Vdose) and mean lung dose (MLD) were analyzed for potential DV predictors. PFT changes were calculated as the difference between pre-RT and post-RT values at 3, 6, and 12 months after RT. Results: Twenty-two patients (37%) developed grade ${\geq}2$ RP. Among clinical factors, tumor location in lower lobe was associated with RP. Among the DV parameters, only MLD >15 Gy was associated with grade ${\geq}2$ RP. There were statistically significant decreases in PFT at all points compared with pre-RT values in grade ${\geq}2$ RP group. MLD was associated with forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) changes at 6 and 12 months. V10 was associated with FVC changes at 12 months. V20 and V30 were associated with FEV1 changes at 6 months and FVC changes at 12 months. Conclusion: After definitive CCRT in patients with NSCLC, MLD >15 Gy and lower lobe tumor location were predictors of grade ${\geq}2$ RP. Pulmonary functions were decreased after CCRT and the magnitude of changes was associated with DV parameters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.987-995
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• 1999

The handoff is a distinctive characteristic of the mobile networks. In the CDMA systems, if base stations support multiple Frequency Assignment (FA), they provide both soft handoff and hard handoff. Under the CDMA environments, the soft handoff guarantees the favorable service quality and the continuity of call connection without interruption, and increases the service capacity of the base stations. This paper proposes call connection control schemes with handoff queue for supporting efficient handoff processing. The proposed schemes are divided into two categories: single handoff queue scheme and multiple handoff queue scheme. We analyze the performance of the proposed call connection control schemes using numerical analysis. From the analysis results, we can say that it is more desirable to avoid hard handoff as long as handoff queues are used. When a single handoff queue used, adaptive scheme that properly mixes avoidable and avoidable hard handoff method under the given traffic condition is more desirable. In case that multiple handoff queues are used, the suitable trade-off needs to be developed between handoff blocking probability and hard handoff probability to guarantee a given blocking probability threshold.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.43-47
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• 1997

This study was carried out in the laboratory to clarify effects of different temperature of Protopulvinaria mangiferae(Green) on development, survivorship and reproduction. Developmental period of the mango shieldscale from crawlers to preoviposition adult decreased as temperature increased. The threshold temperature andthermal constants for the development of one generation were 11.7"C and 1000.0 day-degrees, respectively. At25$^{\circ}$C and 30$^{\circ}$C, survival rate from egg to preoviposition adult were 82% and 6096, respectively. Hatchability ofeggs was more than 99% at both condition. The reproductive period overaged 50 days(2SnC) and 33 days(30$^{\circ}$C). After mature adult began to reporduce, and more than 50% of the crawlers emerged during the firsthalf of their life time. The net reproduction rate per generation(R), mean length of a generation0 and intrinsicrate of natural increase(r, ) were higher at 25$^{\circ}$C than at 30"C, and the values measured at 25$^{\circ}$C were 132.6, 76.2 and 0.064/female/day, respectively.

• Journal of architectural history
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• v.17 no.6
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• pp.67-86
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• 2008

Main theme of this paper is the evaluation of the historical significance of Luciano Baldessari's exhibition works mainly during the Fifties. In order to understand the formal and logical basis of those project, his relationship with the historical Avant-gardes and the consequences expressed in his pavilion projects for the Breda Industrial Company are analyzed. The first part focuses on the influence of Italian Futurism, German Expressionism and Italian Rationalism on the formation and experience of Baldessari during the interwar years. The encounter with these movements determine the interest but also the principles along which Baldessari represents his idea of object, space and place. Specially his professional activities during Fascism would determine his attitude toward political power and the necessity of autonomy in artistic sphere. In the second part, different themes that Baldessari affronted in each project of Breda Pavilions is analyzed. Another important issue regard the historiography of the contemporary architecture. Often, many important works that lies in the threshold of the disciplines such as painting and sculpture and media art were excluded in the history of architecture just because they do not deal with the architectural object. Recently, many elements such as theatrical project and temporary objects are considered as part of urban reality and architecture with acknowledgment of their capacity to create event and situations. Along this thought, not just the reconfiguration on the territory of architecture in present but also the criterion to evaluate the past history of architecture is changing drastically. This study on the pavilions of Baldessari intends to contribute indirectly on the current issue of dominion of architecture, but also to evaluate objectively recent architecture. Consequently, architectural protagonists such as Baldessari and their ephemeral projects would be evaluated compressively in their multiplicity of significance.

• Smart Structures and Systems
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• v.6 no.3
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• pp.277-290
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• 2010

Internationally the load carrying capacity of bridges is decreasing due to material deterioration while at the same time increasing live loads mean that they are often exposed to stresses for which they were not designed. However there are limited resources available to ensure that these bridges are fit for purpose, meaning that new approaches to bridge maintenance are required that optimize both their service lives as well as maintenance costs. Wireless sensor networks (WSNs) provide a tool that could support such an optimized maintenance program. In many situations WSNs have advantages over conventional wired monitoring systems in terms of installation time and cost. In order to evaluate the potential of these systems two WSNs were installed starting in July 2007 on the Humber Bridge and on a nearby approach bridge. As part of a corrosion prevention strategy, a relative humidity and temperature monitoring system was installed in the north anchorage chambers of the main suspension bridge where the main cables of the bridge are anchored into the foundation. This system allows the Bridgemaster to check whether the maximum relative humidity threshold, above which corrosion of the steel wires might occur, is not crossed. A second WSN which monitors aspects of deterioration on a reinforced concrete bridge located on the approach to the main suspension bridge was also installed. Though both systems have provided useful data to the owners, there are still challenges that must be overcome in terms of monitoring corrosion of steel, measuring live loading and data management before WSNs can become an effective tool for bridge managers.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.2
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• pp.57-64
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• 2009

This paper presents the hardware implementation of the pyramidal KLT(Kanade-Lucas-Tomasi) feature tracker. Because of its high computational complexity, it is not easy to implement a real-time KLT feature tracker using general-purpose processors. A hardware implementation of the pyramidal KLT feature tracker using FPGA(Field Programmable Gate Array) is described in this paper with emphasis on 1) adaptive adjustment of threshold in feature extraction under diverse lighting conditions, and 2) modification of the tracking algorithm to accomodate parallel processing and to overcome memory constraints such as capacity and bandwidth limitation. The effectiveness of the implementation was evaluated over ones produced by its software implementation. The throughput of the FPGA-based tracker was 30 frames/sec for video images with size of $720{\times}480$.