• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.345-364
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• 2021

Developments in the understanding of fire behaviour for large open-plan spaces typical of tall buildings have been greatly outpaced by the rate at which these buildings are being constructed and their characteristics changed. Numerous high-profile fire-induced failures have highlighted the inadequacy of existing tools and standards for fire engineering when applied to highly-optimised modern tall buildings. With the continued increase in height and complexity of tall buildings, the risk to the occupants from fire-induced structural collapse increases, thus understanding the performance of complex structural systems under fire exposure is imperative. Therefore, an accurate representation of the design fire for open-plan compartments is required for the purposes of design. This will allow for knowledge-driven, quantifiable factors of safety to be used in the design of highly optimised modern tall buildings. In this paper, we review the state-of-the-art experimental research on large open-plan compartment fires from the past three decades. We have assimilated results collected from 37 large-scale compartment fire experiments of the open-plan type conducted from 1993 to 2019, covering a range of compartment and fuel characteristics. Spatial and temporal distributions of the heat fluxes imposed on compartment ceilings are estimated from the data. The complexity of the compartment fire dynamics is highlighted by the large differences in the data collected, which currently complicates the development of engineering tools based on physical models. Despite the large variability, this analysis shows that the orders of magnitude of the thermal exposure are defined by the ratio of flame spread and burnout front velocities (V_S / V_BO), which enables the grouping of open-plan compartment fires into three distinct modes of fire spread. Each mode is found to exhibit a characteristic order of magnitude and temporal distribution of thermal exposure. The results show that the magnitude of the thermal exposure for each mode are not consistent with existing performance-based design models, nevertheless, our analysis offers a new pathway for defining thermal exposure from realistic fire scenarios in large open-plan compartments.

• Korean Journal of Environment and Ecology
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• v.37 no.1
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• pp.70-75
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• 2023

This study was conducted from October 2021 to October 2022 at Gulup island, Incheon, South Korea, to identify activity patterns of Formosan sika deer (Cervus nippon taiouanus) introduced in island areas, using camera trapping. We described the daily activity patterns of Formosan sika deer in each season by analyzing kernel density estimates of capture frequency and checked seasonal differences in daily activity patterns by analyzing the overlap coefficient between seasons. Formosan sika deers introduced to Gulup island showed a crepuscular behavior pattern only in winter and no distinct pattern from spring to fall. The crepuscular behavior pattern is typical for deers to reduce the risk of predation, and it is determined that Formosan sika deers introduced to Gulup island were affected by population control of the species by the local government in the winter. It was in contrast to the fact that human activities, such as backpacking, frequently carried out from spring to fall, did not affect the behavior of Formosan sika deers. Moreover, low winter temperatures have been shown to affect the nocturnal activities of Formosan sika deers in winter. The behavior patterns of Formosan sika deers overlapped least between summer and winter due to cold winter weather and population control. The relationship between the temporal status of Formosan sika deers and seasonal temperature confirmed in this study can be important basic ecological data for establishing control measures of Formosan sika deers introduced not only in islands but also in inland.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.217-228
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• 2023

Video instance segmentation is an intelligent visual task with high complexity because it not only requires object instance segmentation for each image frame constituting a video, but also requires accurate tracking of instances throughout the frame sequence of the video. In special, human instance segmentation in drama videos has an unique characteristic that requires accurate tracking of several main characters interacting in various places and times. Also, it is also characterized by a kind of the class imbalance problem because there is a significant difference between the frequency of main characters and that of supporting or auxiliary characters in drama videos. In this paper, we introduce a new human instance datatset called MHIS, which is built upon drama videos, Miseang, and then propose a novel video data augmentation method, CDVA, in order to overcome the data imbalance problem between character classes. Different from the previous video data augmentation methods, the proposed CDVA generates more realistic augmented videos by deciding the optimal location within the background clip for a target human instance to be inserted with taking rich spatio-temporal context embedded in videos into account. Therefore, the proposed augmentation method, CDVA, can improve the performance of a deep neural network model for video instance segmentation. Conducting both quantitative and qualitative experiments using the MHIS dataset, we prove the usefulness and effectiveness of the proposed video data augmentation method.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.7
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• pp.369-376
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• 2002

Although LRU is not adequate for database that has non-uniform reference pattern, it has been adopted in most database systems due to the absence of the proper alternative. We analyze database block reference pattern with the realistic database trace. Based on this analysis, we propose a new cache replacement policy. Trace analysis shows that extremely non-popular blocks take up about 70 % of the entire blocks. The influence of recency on blocks' re-reference likelihood is at first strong due to temporal locality, however, it rapidly decreases and eventually becomes negligible as stack distance increases. Based on this observation, RCB(Reference Characteristic Based) cache replacement policy, which we propose in this paper, classifies the entire blocks into four block groups by blocks' recency and re-reference likelihood, and operates different priority evaluation methods for each block group. RCB policy evicts non-popular blocks more quickly than the others and evaluates the priority of the block by frequency that has not been referenced for a long time. In a trace-driven simulation, RCB delivers a better performance than the existing polices(LRU, 2Q, LRU-K, LRFU). Especially compared to LRU. It reduces miss count by 5~l2.7%. Time complexity of RCB is O(1), which is the same with LRU and 2Q and superior to LRU-K(O(log$_2$N)) and LRFU(O(l) ~ O(log$_2$N)).

• Journal of Science of Art and Design
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• v.1
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• pp.189-226
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• 1999

The purpose of this paper is to examine the common characteristics of late 20th century interior design style and the post-modern thinking system. A period has its own predominant spirit which determine the tendency of art, and the ubiquitous power in the spirit decides the period's pattern of art. Therefore the interior design style belongs to general art sphere that has its own individual character derived from the dominant power of the controlling system. Paying special attention to this understanding, the auther has processed this paper by combining the post-modem thinking with special characteristics of each of the 20th century interior design style. Until now, researches have been focused on the individual style of post-modern design; however, a general research comprising the whole characteristics of expression has not been made. Accordingly, the rationale of emphasizing the general point of view is establshed. Also, this study suggests a model applicable to studies concerning other art area. This type of methodology is receving more attention as an approach investigating new art ideology for researching post-modern thinking and late 20th century art styles. The conclusions are as follows: First, the distinctive expressions of postmodernism appear to be characteristic of illusion, metaphor, pluralism, decoration, and symmetry, Those of late modernism appear to be the characteristic of complicated simplicity and symplified complexity, passiveness of symbolism and harmony, indeterminacy of form and space, and unintentional decorativeness. And the characteristics of deconstructionism are spatial difference and temporal defferal, and un-reductive and non formal abstractiveness of the space, unfinishness, chance, and secretiveness of individual style. Second, the disinctive expression seems to share common characteristics with postmodern thinking. The best examples are pluralism, non-formalism, populism, and historicism, originating from the deconstruction of 'meta-narrative'. Third, based on the second conclusion, general distinctive expression could be simplified as chacteristics of plurality, hybridity, and indeterminacy. These expressive chacteristics appear to be automatically connected with general postmodern thinking. Last, in consideration of the above conclusion, the extreme generality could be distinctively clarified as 'textural co-exsistence'. Accordingly, the author might confirm that 'textural co-existence' originated from the text that comes from postmodern thinking. In conclusion, design expression of late 20th century interior design accepts the ?universal theme of ubiquitous postmodern thinking. And universal expressions and supreme generality can be common analysis tools for understanding and studying complicated late 20th century interior design.

• Journal of Intelligence and Information Systems
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• v.15 no.2
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• pp.33-48
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• 2009

Capsule endoscopy is one of the most remarkable inventions in last ten years. Causing less pain for patients, diagnosis for entire digestive system has been considered as a most convenience method over a normal endoscope. However, it is known that the diagnosis process typically requires very long inspection time for clinical experts because of considerably many duplicate images of same areas in human digestive system due to uncontrollable movement of a capsule endoscope. In this paper, we propose a method for clinical diagnosticians to get highly valuable information from capsule-endoscopy video. Our software system consists of three global maps, such as movement map, characteristic map, and brightness map, in temporal domain for entire sequence of the input video. The movement map can be used for effectively removing duplicated adjacent images. The characteristic and brightness maps provide frame content analyses that can be quickly used for segmenting regions or locating some features(such as blood) in the stream. Our experiments show the results of four patients having different health conditions. The result maps clearly capture the movements and characteristics from the image frames. Our method may help the diagnosticians quickly search the locations of lesion, bleeding, or some other interesting areas.

• The Journal of the Acoustical Society of Korea
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• v.32 no.1
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• pp.22-31
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• 2013

In this paper, we propose a method that estimates the channel response from underwater communication signals with MMSE (Minimun Mean Squared Error) and detects dominant components automatically based on power of response components using CFAR (Constant False Alarm Rate). Statistical characteristics are analyzed with variation of magnitude and phase and time coherence via experimental data obtained by drifting transmitter and receiver. We show that bit error rate has small difference, 1.2 times, compared with the case using every channel information estimated within data period when estimation and equalization is performed with extracted characteristic obtained by the proposed method.

• International Journal of Fluid Machinery and Systems
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• v.4 no.4
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• pp.367-374
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• 2011

Water hammer pumps can effectively use the water hammer phenomenon in long-distance pipeline networks that include pumps and allow fluid transport without drive sources, such as electric motors. The results of experiments that examined the effect of the geometric form of water hammer pumps by considering their major dimensions have been reported. In addition, a paper has also been published analyzing the water hammer phenomenon numerically by using the characteristic curve method for comparison with experimental results. However, these conventional studies have not fully evaluated the pump performance in terms of pump head and flow rate, common measures indicating the performance of pumps. Therefore, as a first stage for the understanding of water hammer pump performance in comparison with the characteristics of typical turbo pumps, the previous paper experimentally examined how the hydrodynamic characteristics were affected by the inner diameter ratio of the drive and lifting pipes, the form of the air chamber, and the angle of the drive pipe. To understand the behavior of the components attached to the valve chamber and the air chamber that affects the performance of water hammer pumps, the previous study also determined the relationship between the water hammer pump performance and temporal changes in valve chamber and air chamber pressures according to the air chamber capacity. For the geometry of components attached to the drain valve, which is another major component of water hammer pumps, this study experimentally examines how the water hammer pump performance is affected by the length of the spring and the angle of the drain pipe.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.279-285
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• 2020

In the era of the Fourth Industrial Revolution, there are many sensors around. People and things are connected to these sensors to the internet. Numerous connected sensors produce the latest data in seconds, and these data are stacked with big data of unimaginable size. Because personal information can be contained in any place of data produced, device and system protection are needed. Digital twins are virtual models that accurately reflect the status information of physical assets and systems that utilize them. The characteristic of digital twin is that digital twin itself has temporal and structural identity enough to represent the object of reality. In the virtual environment the reproduced reality, it continuously simulates and it virtuals of the point of time or the future, the replica can be created. Therefore, this study cited factors threatening personal information in the era of the Fourth Industrial Revolution. And proposed using digital twin technology that can simulate in real-time to overcome the risk of personal information hacking.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.174-179
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• 2017

We designed the CMOS analog integrate and fire (I&F) neuron circuit for driving memristor based on resistive-switching random access memory (RRAM). And we fabricated the RRAM device that have $HfO_2$ switching layer using atomic layer deposition (ALD). The RRAM device has gradual set and reset characteristics. By spice modeling of the synaptic device, we performed circuit simulation of synaptic device and CMOS neuron circuit. The neuron circuit consists of a current mirror for spatial integration, a capacitor for temporal integration, two inverters for pulse generation, a refractory part, and finally a feedback part for learning of the RRAM. We emulated the spike-timing-dependent-plasticity (STDP) characteristic that is performed automatically by pre-synaptic pulse and feedback signal of the neuron circuit. By STDP characteristics, the synaptic weight, conductance of the RRAM, is changed without additional control circuit.