• The Transactions of the Korea Information Processing Society
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• v.13 no.2
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• pp.34-40
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• 2024

Secret sharing is a cryptographic technique that involves dividing a secret or a piece of sensitive information into multiple shares or parts, which can significantly increase the confidentiality of a secret. There has been a lot of research on secret sharing for different contexts or situations. Tassa's conjunctive secret sharing method employs polynomial derivatives to facilitate hierarchical secret sharing. However, the use of derivatives introduces several limitations in hierarchical secret sharing. Firstly, only a single group of participants can be created at each level due to the shares being generated from a sole derivative. Secondly, the method can only reconstruct a secret through conjunction, thereby restricting the specification of arbitrary secret reconstruction conditions. Thirdly, Birkhoff interpolation is required, adding complexity compared to the more accessible Lagrange interpolation used in polynomial-based secret sharing. This paper introduces the multi-compartment secret sharing method as a generalization of the conjunctive hierarchical secret sharing. Our proposed method first encrypts a secret using external groups' shares and then generates internal shares for each group by embedding the encrypted secret value in a polynomial. While the polynomial can be reconstructed with the internal shares, the polynomial just provides the encrypted secret, requiring external shares for decryption. This approach enables the creation of multiple participant groups at a single level. It supports the implementation of arbitrary secret reconstruction conditions, as well as conjunction. Furthermore, the use of polynomials allows the application of Lagrange interpolation.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.148-156
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• 2008

Statement of problems: Self-etch adhesives exhibit some clinical benefits such as ease of manipulation and reduced technique-sensitivity. Nevertheless, some concern remains regarding the bonding effectiveness of self-etch adhesives to enamel, in particular when so-called 'mild' self-etch adhesives are employed. This study compared the microtensile bond strengths to ground enamel of the two-step self-etch adhesive Clearfil SE Bond (Kuraray) to the three-step etch-and- rinse adhesive Scotchbond Multi-Purpose (3M ESPE) and the one-step self-etch adhesive iBond (Heraeus Kulzer). Purpose: The purpose of this study was to determine the effect of a preceding phosphoric acid conditioning step on the bonding effectiveness of a two-step self-etch adhesive to ground enamel. Material and methods: The two-step self-etch adhesive Clearfil SE Bond non-etch group, Clearfil SE Bond etch group with prior 35% phosphoric acid etching, and the one-step self-etch adhesive iBond group were used as experimental groups. The three-step etch-and-rinse adhesive Scotchbond Multi-Purpose was used as a control group. The facial surfaces of bovine incisors were divided in four equal parts cruciformly, and randomly distributed into each group. The facial surface of each incisor was ground with 800-grit silicon carbide paper. Each adhesive group was applied according to the manufacturer's instructions to ground enamel, after which the surface was built up using Light-Core (Bisco). After storage in distilled water at $37^{\circ}C$ for 1 week, the restored teeth were sectioned into enamel beams approximately 0.8*0.8mm in cross section using a low speed precision diamond saw (TOPMET Metsaw-LS). After storage in distilled water at $37^{\circ}C$ for 1 month, 3 months, microtensile bond strength evaluations were performed using microspecimens. The microtensile bond strength (MPa) was derived by dividing the imposed force (N) at time of fracture by the bond area ($mm^2$). The mode of failure at the interface was determined with a microscope (Microscope-B nocular, Nikon). The data of microtensile bond strength were statistically analyzed using a one-way ANOVA, followed by Least Significant Difference Post Hoc Test at a significance level of 5%. Results: The mean microtensile bond strength after 1 month of storage showed no statistically significant difference between all adhesive groups (P>0.05). After 3 months of storage, adhesion to ground enamel of iBond was not significantly different from Clearfil SE Bond etch (P>>0.05), while Clearfil SE Bond non-etch and Scotchbond Multi-Purpose demonstrated significantly lower bond strengths (P<0.05), with no significant differences between the two adhesives. Conclusion: In this study the microtensile bond strength to ground enamel of two-step self-etch adhesive Clearfil SE Bond was not significantly different from three-step etch-and-rinse adhesive Scotchbond Multi-Purpose, and prior etching with 35% phosphoric acid significantly increased the bonding effectiveness of Clearfil SE Bond to enamel at 3 months.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.504-512
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• 2022

To examine the distribution of internal solar radiation within various locations in multi-span greenhouses, the solar radiation, light transmittance, and accumulated radiation at the central and lateral sections were analyzed by dividing 8:30 to 12:30 in the morning and 12:35 to 16:30 in the afternoon. The growth and yield of tomatoes within these sections were also compared. In the morning, the solar radiation of the central section and the side section was 275.2 W·m^-2 and 314.9 W·m^-2, while in the afternoon, it was 314.9 W·m^-2 and 313.9 W·m^-2, respectively. The light transmittance and accumulated radiation were also low, confirming the low distribution of solar radiation in the central (connecting) section of the multi-span greenhouses. The growth survey revealed no significant difference. The final yield of tomatoes per plant was 4,828 g in the central section and 4,851 g in the lateral section, but there was no significant difference in the central section compared to the lateral section by 0.5%. However, the amount of solar radiation as per time in the central section is higher than the light compensation point, 60 W·m^-2, and slightly lower than the light saturation point of tomatoes, i.e., 281 W·m^-2. The results of this study can help in greenhouse design based on the insolation environment.

• Journal of Korean Society of Transportation
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• v.19 no.4
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• pp.73-84
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• 2001

Korean Highway Capacity Manual applies 7 adjustment factors to estimate saturation flows at signalized intersections. Among the adjustment factors, the right-turn adjustment factor uses equation hard to understand and requires complicated computing process comparing other adjustment factors. Thus. this study was conducted in order to suggest a new technique of estimating the right-turn adjustment factor which is easy to understand and simple to computer by having reasonable degree of accuracy. In this study the right-turn saturation flow ratios which are important in estimating the factor are suggested and the equation to estimate the volume of right-turn on red signal(RTOR) is developed based on observed data. The right-turn saturation flow rates can be estimated according to turning radius and number of lanes of crossing road dividing right-turn lanes into canalized and uncanalized lanes. The RTOR volume is estimated using the proportion of the time during which RTOR is possible to the whole time of red signal according to the through traffic volume per lane of the approach at signalized intersections. The technique of estimating the right-turn adjustment factor suggested in this study, which follows the HCM2000 of U.S. in principal, first judges the right-turn lane to be used exclusively for right-turn or not by employing the RTOR factor and the judging equation developed in this study. Next, if the right-turn lane is not exclusive right-turn lane, the shared right-turn lane is classified into single lane approach or multi lane approach. Thus, a total of three methods of estimating the right-turn adjustment factor to the three cases are suggested in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.81-88
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• 2012

This present research was carried out by dividing two parts; field surveying and data processing, in order to analyze changed patterns of a shoreline. Firstly, the shoreline information measured by the precise GPS positioning during long duration was collected. Secondly, the algorithm for detecting an auto boundary with regards to the changed shoreline with multi-image data was developed. Then, a comparative research was conducted. Haeundae beach which is one of the most famous ones in Korea was selected as a test site. RTK-GPS surveying had been performed overall eight times from September 2005 to September 2009. The filed test by aerial Lidar was conducted twice on December 2006 and March 2009 respectively. As a result estimated from both sensors, there is a slight difference. The average length of shoreline analyzed by RTK-GPS is approximately 1,364.6 m, while one from aerial Lidar is about 1,402.5 m. In this investigation, the specific algorithm for detecting the shoreline detection was developed by Visual C++ MFC (Microsoft Foundation Class). The analysis result estimated by aerial photo and satellite image was 1,391.0 m. The level of reliability was 98.1% for auto boundary detection when it compared with real surveying data.

• Journal of Gifted/Talented Education
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• v.25 no.2
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• pp.321-337
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• 2015

The purpose of the present study is to examine elementary gifted students' perceptions on bias against creativity utilizing concept mapping approach. Twelve elementary gifted students participated in the group brainstorming and produced 55 final statements. Based on these statements, the multi-dimensional scale and hierarchial cluster analysis using dissimilarity matrix were performed. Average stress value was .30 which is appropriate for a two-dimensional concept mapping study. In addition, a questionnaire survey using likert 6 points scale was carried out targeting 132 elementary gifted students to analyze the degree of sympathy on their anti-creativity bias perception. The findings are as follow: First, four categories were concluded dividing gifted students' perceptions on bias against creativity from the hierarchial cluster analysis with X-Y coordinate matrix, these were 'Contradictory attitudes to creativity', 'Low evaluation for creativity', 'Forced to predetermined rules and ideas', and 'Aversion to new things'. Second, elementary gifted students were sympathetic to the order 'Forced to predetermined rules and ideas'(M=4.16), 'Aversion to new things'(M=3.68), 'Contradictory attitudes to creativity'(M=3.55) and 'Low evaluation for creativity'(M=3.30). This study aims to examine, analyze and categorize various relevant factors related to elementary gifted students' perceptions on bias against creativity. Implications of the study related to the present and future creative education were discussed in depth.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.191-201
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• 2018

In this present study, we, for the first time, retrieved total column of ozone ($O_3$) and tropospheric ozone vertical profile using the Optimal Estimation (OE) method based on the MAX-DOAS measurement at the Yonsei University in Seoul, Korea. The optical density fitting is carried out using the OE method to calculate ozone columns. The optical density between the MAX-DOAS data obtained by dividing the measured intensities for each viewing elevated angle by those at the zenith angle. The retrieved total columns of the ozone are 375.4 and 412.6 DU in the morning (08:13) and afternoon (17:55) on 23 May, 2017, respectively. In addition, under 10 km altitude, the $O_3$ vertical profile was retrieved with about 5% of retrieval uncertainty. However, above 10 km altitude, the $O_3$ vertical profile retrieval uncertainty was increased (>10%). The spectral fitting errors are 16.8% and 19.1% in the morning and afternoon, respectively. The method suggested in this present study can be useful to measure the total ozone column using the ground-based hyper-spectral UV sensors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.121-126
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• 2017

Recently, a lot of people use touch-pen devices such as smart phones and tab computers. To generate the picture and text, a user can give input or control the touch-pen device through simple or multi-touch gestures by touching the screen with a special stylus pen and/or one or more fingers. The accuracy and response time from the moment of contact with the touch board is very important to the touch device. Therefore, research is needed to find a way of removing the noise included in the touch signal quickly and efficiently. In this paper, we propose a method for removing a noise mixed in with a touch point coordinate which has been caused by a input pen on the touch screen. For effective filtering, the fast sampling of the coordinate corresponding to the noise from the input signal is required primarily. Secondly the total compensation of the touch coordinates using the characteristics of the B-Spline curve is applied to correct coordinates of the points. This method can ensure a real-time response than other algorithms. The applied performance evaluation method is comparing error pixels with evaluation values by dividing 10 intervals on the touch pad diagonally. Usually the average error is 7.1 pixels but our proposed method shows an average 4.1 errors. Therefore, our proposed touch pen method can express the input signal on the coordinates more correctly.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.123-132
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• 2006

In this paper, the digital video and audio system is improved so that various digital video data formats in DVD disc, and digital audio data formats through the S/PDIF ports may be decoded. It is not easy to implement all decoding functions of video and audio by a DVD processor. The special structure in audio decoding circuit is proposed in this system so as to have simultaneously almost same video and audio performance in quality. By dividing the decoding circuit separately into video and audio part, the audio quality can be dramatically improved together with supporting several audio formats and with several effects. In order to satisfy the perfect audio system to support to audio decoding formats, it is just enough to get the expensive, complicated decoder. However, it may be not easy to get this expensive decoder in near future. Therefore it is rather to adopt the downloading method by which the host should download the appropriate code into memory by detecting the corresponding audio bit streams. It is proved that this method may be efficient in the point of sharing resource of audio data for video decoding.

• Journal of Korea Spatial Information System Society
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• v.8 no.3
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• pp.105-115
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• 2006

A sensor network which uses DCS(Data-Centric Storage) stores the same data into the same sensor node. Thus it has a hot spot problem when the sensor network grows and the same data arise frequently. In the past researches of the sensor network using DCS, the hot spot problem caused by growing the sensor network was ignored because they only concentrated on managing stored sensor data efficiently. In this paper, we proposed a non-equal region split method that supports efficient scalability on storing multi-dimensional sensor data. This method can reduce the storing cost, as the sensor network is growing, by dividing whole space into regions which have the same number of sensor nodes according to the distribution of sensor nodes, and storing and managing sensor data within each region. Moreover, this method can distribute the energy consumption of sensor nodes by increasing the number of regions according to the size of the sensor network, the number of sensor nodes within the sensor network, and the quantity of sensor data. Therefore it can help to increase the life time and the scalability of the sensor network.