• The KIPS Transactions:PartA
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• v.14A no.6
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• pp.347-356
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• 2007

In designing a branch predictor, in addition to accuracy, microarchitects should consider power consumption, especially for embedded processors. This paper proposes a power-aware branch predictor, which is based on the gshare predictor, by accessing the BTB (Branch Target Buffer) only when the prediction from the PHT (Pattern History Table) is taken. To enable the selective access to the BTB, the PHT in the proposed branch predictor is accessed one cycle earlier than the traditional PHT to prevent the additional delay. As a side effect, two predictions from the PHT are obtained through one access to the PHT, which leads to more power savings. The proposed branch predictor reduces the power consumption, not requiring any additional storage arrays, not incurring additional delay (except just one MUX delay) and never harming accuracy. Simulation results show that the proposed predictor reduces the power consumption by $35{\sim}48%$ compared to the traditional predictor.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.223-236
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• 2019

Resistivity surveys can identify the distribution of geological units and structures (including fragmented fault zones), the extent of weathered and modified geological strata, and the characteristics of groundwater. This study aims to analyze the underground sedimentary layers and geological structures near the Nari and Albong Basins of Ulleung-do, Korea, focusing on six survey lines to identify the spatial trends in subsurface resistivity. A modified dipole array method (D method) was employed, combining resistivity results obtained by existing dipole array methods (A and C methods). The modified method provides optimal analysis of the cross-section of underground resistivity, and shows a clear boundary between a low-resistivity zone (${\leq}500{\Omega}{\cdot}m$) of sedimentary layers and weak zones, and a high-resistivity zone (${\geq}5,000{\Omega}{\cdot}m$) of volcanic rock (trachyandesite). The estimated average thickness of the sedimentary layers is 50~100 m for the Albong Basin and 100~200 m for the Nari Basin. An anomaly zone, different from the weak zone in the bedrock, is identified as a caldera fault, and the low-resistivity zone extends from the surface down to the lowest survey depths.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.481-504
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• 2010

Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.442-448
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• 2002

In the earth telescope for space observation, the adaptive optical (AO) system that immediately compensates atmospheric turbulence is helpful to get high-resolution images. An adaptive optics for earth telescopes is very attractive, since the Earth telescopes can be made at lower costs and have larger optical apertures than space telescopes. Generally. in order to remove the wavefront error produced by atmospheric turbulence, a deformable mirror, whose surface shape changes in a controllable way in response to a drive signal, is used. The characteristics and patterns of actuators are very important for the effective control of a deformable mirror. The mirror surface shape deformed by one actuator is defined as an influence function and the deformable mirror can be effectively modeled and designed using this influence function. In this paper. by simplifying the actual influence function obtained by FEM analyses into the Gaussian function and introducing the coupling coefficient between actuators, the influence function is constructed. The proper coupling coefficient of the target system can be obtained by performance analyses of a deformable mirror for various coupling coefficients. Using the constructed influence function, the deformable mirror with equally spaced triangular and square actuator patterns is analyzed for various spacings and an effective actuator pattern is proposed.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.749-754
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• 2021

In order to maximize the matching ratio between the scintillation pixel and the photosensor of the PET detector using a small number of photosensor, various arrays of scintillation pixels and four photosensors were used. The array of scintillation pixels consisted of six cases from 6 × 6 to 11 × 11. The distance between the photosensors was applied equally to all scintillation pixels, and the arrangement was expanded by reducing the size of scintillation pixel. DETECT2000 capable of light simulation was used to acquire flood images of the designed PET detectors. At the center of each scintillation pixel array, light generated through the interaction between extinction radiation and scintillation pixels was generated, and the light was detected through for four photosensors, and then a flood image was reconstructed. Through the reconstructed flood image, we found the largest arrangement in which all the scintillation pixels can be distinguished. As a result, it was possible to distinguish all the scintillation pixels in the flood image of 8 × 8 scintillation pixel array, and from the 9 × 9 scintillation pixel flood image, the two edge scintillation pixels overlapped and appeared in the image. At this time, the matching ratio between the scintillation pixel and the photosensor was 16:1. When a PET system is constructed using this detector, the number of photosensors used is reduced and the cost of the oveall system is expected to be reduced through the simplification of the signal processing circuit.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.275-284
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• 2018

In this study we propose a hybrid color-filter design method in which a nanohole array and a nanodisk array are separated by nanopillars of the material AZ 1500. We propose a design method for an RGB color filter, using the tendency of transmitted light according to each design variable. Especially we analyzed the intensity distribution of the electric field in the cross section, and set the height of the nanopillars so that the local surface-plasmon resonances generated in the two different arrays do not affect each other. The optical characteristics of the optimized color filter are as follows: In the case of the red filter, the ratio of the wavelength band expressing red in the visible broadband is 55.01%, and the maximum transmittance is 41.53%. In the case of the green filter, the ratio of the wavelength band expressing green is 40.20%, and the maximum transmittance is 42.41%. In the case of the blue filter, the ratio of the wavelength band expressing blue is 32.78%, and the maximum transmittance is 30.27%. We expect to improve the characteristics of color filters integrated in industrial devices by this study.

• Korean Journal of Cognitive Science
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• v.32 no.3
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• pp.117-139
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• 2021

The way of change detection in which presence of a different item is determined between memory and test arrays with a brief in-between time interval resembles how visual search is done considering that the different item is searched upon the onset of a test array being compared against the items in memory. According to the resemblance, the present study examined whether varying the probability of change occurrence in a visual short-term memory-based change detection task can influence the aspect of response-decision making (i.e., change prevalence effect). The simple-feature change detection task in the study consisted of a set of four colored boxes followed by another set of four colored boxes between which the participants determined presence or absence of a color change from one box to the other. The change prevalence was varied to 20, 50, or 80% in terms of change occurrences in total trials, and their change detection errors, detection sensitivity, and their subsequent RTs were analyzed. The analyses revealed that as the change prevalence increased, false alarms became more frequent while misses became less frequent, along with delayed correct-rejection responses. The observed change prevalence effect looks very similar to the target prevalence effect varying according to probability of target occurrence in visual search tasks, indicating that the background principles deriving these two effects may resemble each other.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.13-13
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• 2019

Soybean (Glycine max L. (Merr) is commonly consumed and found in major foods including soymilk, soy sauce, tofu, and soy sprout in Korea and east Asia. In addition, it is common to cook the whole seeds with rice. Soybean is known to have ranges of health benefits including antiaging, anticancer, neuroprotective and antidiabetic taken either as supplement or dietary food. Anthocyanins and flavonoids in G. max are found to be the main contributors to such wide arrays of health benefits. Due to increasing economic values of soybean, development of specialty soybean cultivars is becoming an area of interest worldwide. In this study, 746 black soybean accessions from National Agrobiodiversity Center were characterized as part of an attempt to identify important germplasms of G. max. Seed coats of each accession were analyzed for their total anthocyanin, cyanidin 3-O-Glucoside (C-3-O-G), delphinidin 3-O-glucoside (D-3-O-G), petunidin-3-O-glucoside (Pt-3-O-G), and their whole seeds for crude protein contents. HPLC was used to determine and quantify the anthocyanin compositions while crude protein was determined using Kjeldahl method by Kjeltec auto-analyzer (Kjeltec 8400, Foss, Sweden). Accessions were grouped according to their anthocyanins and protein contents; the mean content of which were correlated to agronomic traits including maturity date, one hundred seed weight, cotyledon color and seed lust color. The results indicated that the total anthocyanin content (TAC) ranged from 273.77 to 6250.52 mg/100 g, with mean value of 1853.03 mg/100 g while the crude protein content (CPC) being between 33.43 and 47.51%, with mean value of 40.81%. The highest number of accessions (45.97%) showed TAC between 1000~1900 mg/100 g while 30.96% of accessions showed CPC between 41~43%. Among the 746 accessions considered, 11 (IT142935, 175818, 175855, 177191, 177209, 177211, 177214, 177216, 177218, 177220, 177274) of them showed TAC above 4000 mg/100 g. C-3-O-G was found to be the major contributor to TAC showing strong correlation. Accessions with green cotyledon color showed high mean TAC compared to those having yellow cotyledon color, and accessions with dull seed lust color showed high mean TAC than those having shiny seed lust color. One hundred seeds weight and maturity date showed positive correlation with all anthocyanin contents, except for Pt-3-O-G in the latter case. The overall result of the present study could be used as background for developing new black soybean cultivars and breeds with high anthocyanin and protein contents. The result depicted that many of the accessions could be used as potential parental lines.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.267-274
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• 2022

In this paper, we report the design and fabrication of binary diffractive optical elements (DOEs) for random-dot-pattern projection for Schlieren imaging. We selected the binary phase level and a pitch of 10 ㎛ for the DOE, based on cost effectiveness and ease of manufacture. We designed the binary DOE using an iterative Fourier-transform algorithm with binary phase optimization. During initial optimization, we applied a computer-generated pseudorandom dot pattern of uniform intensity as a target pattern, and found significant intensity nonuniformity across the field. Based on the evaluation of the initial optimization, we weighted the target random dot pattern with Gaussian profiles to improve the intensity uniformity, resulting in the improvement of uniformity from 52.7% to 90.8%. We verified the design performance by fabricating the designed binary DOE and a beam projector, to which the same was applied. The verification confirmed that the projector produced over 10,000 random dot patterns over 430 mm × 430 mm at a distance of 5 meters, as designed, but had a slightly less uniformity of 84.5%. The fabrication errors of the DOE, mainly edge blurring and spacing errors, were strong possibilities for the difference.

• Journal of the Korean Society of Radiology
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• v.16 no.2
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• pp.157-162
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• 2022

Since preclinical positron emission tomography imaging is performed on small animals that are very small compared to the human body, a detector with excellent spatial resolution is required. For this purpose, a system was constructed using a detector using small scintillation pixels. Since the size of the currently developed and used photosensors is limited, excellent spatial resolution can be obtained when the minimum scintillation pixel and maximum array are used. In this study, the size of the photosensor is fixed and various scintillation pixel arrays are configured to match the size of the scintillation pixels, so that no overlap occurs in the flood image and the maximum scintillation pixel array in which all scintillation pixels are distinguished. For this purpose, DETECT2000, which can simulate a detector module composed of a scintillator and an photosensor, was used. A photosensor consisting of a 4 × 4 array of 3 mm × 3 mm pixels was used, and the scintillation pixel array was configured from 8 × 8 to 13 × 13, and simulations were performed. A flood image was constructed using the data obtained from the photosensor pixel, and the maximum scintillation pixel array that does not overlap the image was found through the flood image and the profile. As a result, the size of the scintillation pixel array in which all scintillation pixels are imaged without overlapping each other in the flood image was 11 × 11.