• Journal of Korean Society of Transportation
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• v.18 no.3
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• pp.55-76
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• 2000

We propose a general solution methodology for identifying the optimal aggregation interval sizes as a function of the traffic dynamics and frequency of observations for four cases : i) link travel time estimation, ii) corridor/route travel time estimation, iii) link travel time forecasting. and iv) corridor/route travel time forecasting. We first develop statistical models which define Mean Square Error (MSE) for four different cases and interpret the models from a traffic flow perspective. The emphasis is on i) the tradeoff between the Precision and bias, 2) the difference between estimation and forecasting, and 3) the implication of the correlation between links on the corridor/route travel time estimation and forecasting, We then demonstrate the Proposed models to the real-world travel time data from Houston, Texas which were collected as Part of the Automatic Vehicle Identification (AVI) system of the Houston Transtar system. The best aggregation interval sizes for the link travel time estimation and forecasting were different and the function of the traffic dynamics. For the best aggregation interval sizes for the corridor/route travel time estimation and forecasting, the covariance between links had an important effect.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1440-1448
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• 2014

Co(II)-tetrasulfonated phthalocyanine (CoTSP) is known to be aggregated to dimer at high concentration levels in water. A study on the aggregation of CoTSP using multivariate curve resolution analysis of the visible absorbance spectra over a concentration range of 30, 40 and 50 ${\mu}M$ in the presence of dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), acetonitrile (AN) and ethanol (EtOH) in the concentration range of 0 to 3.57 M is conducted. A hard modeling-based multivariate curve resolution method was applied to determine the dissociation constants of the CoTSP aggregates at various temperatures ranging from 25, 45 and $65^{\circ}C$ and in the presence of various co-solvents. Dissociation constant for aggregation was increased and then decrease by temperature and concentration of phthalocyanine, respectively. Utilizing the vant Hoff relation, the enthalpy and entropy of the dissociation equilibriums were calculated. For the dissociation of both aggregates, the enthalpy and entropy changes were positive and negative, respectively. Molecular dynamics simulation of cosolvent effect on CoTSP aggregation was done to confirm spectroscopy results. Results of radial distribution function (RDF), root mean square deviation (RMSD) and distance curves confirmed more effect of polar solvent to decrease monomer formation.

• Journal of Ginseng Research
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• v.17 no.2
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• pp.131-134
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• 1993

Panaxadiol (PD) from Korean red ginseng C.A. Meyer did not control the concentration of cytosolic free $Ca^{2+}$ influxes by thrombin (5 $\mu$/ml). However, PD strongly inhibited the synthesis of thromboxane. $A_2$ (TX$A_2$) in the aggregation of human platelets induced by thrombin (5 $\mu$/ml). These rexults suggest that PD blocks the any Pathway transforming to TX$A_2$ from arachidonic acid (AA) which release out of plasma membrane phospholipids by $Ca^{2+}$-dependent phospholipase C or phospholipase $A_2$. It may be also concluded that PD has the antiplatelet function by inhibiting the synthesis of TX$A_2$, which known to be the potent stimulator of the aggregation of human platelet.

• Journal of KIISE
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• v.44 no.7
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• pp.703-709
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• 2017

Outsourcing databases is to offload storage and computationally intensive tasks to the third party server. Therefore, data owners can manage big data, and handle queries from clients, without building a costly infrastructure. However, because of the insecurity of network systems, the third-party server may be untrusted, thus the query results from the server may be tampered with. This problem has motivated significant research efforts on authenticating various queries such as range query, kNN query, function query, etc. Although aggregation queries play a key role in analyzing big data, authenticating aggregation queries has not been extensively studied, and the previous works are not efficient for data with high dimension or a large number of distinct values. In this paper, we propose the AMR-tree that is a data structure, applied to authenticate aggregation queries. We also propose an efficient proof construction method and a verification method with the AMR-tree. Furthermore, we validate the performance of the proposed algorithm by conducting various experiments through changing parameters such as the number of distinct values, the number of records, and the dimension of data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.833-842
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• 2017

In this study, the design methodology of radial basis function neural networks based on incremental K-means clustering is introduced for learning and processing the big data. If there is a lot of dataset to be trained, general clustering may not learn dataset due to the lack of memory capacity. However, the on-line processing of big data could be effectively realized through the parameters operation of recursive least square estimation as well as the sequential operation of incremental clustering algorithm. Radial basis function neural networks consist of condition part, conclusion part and aggregation part. In the condition part, incremental K-means clustering algorithms is used tweights of the conclusion part are given as linear function and parameters are calculated using recursive least squareo get the center points of data and find the fitness using gaussian function as the activation function. Connection s estimation. In the aggregation part, a final output is obtained by center of gravity method. Using machine learning data, performance index are shown and compared with other models. Also, the performance of the incremental K-means clustering based-RBFNNs is carried out by using PSO. This study demonstrates that the proposed model shows the superiority of algorithmic design from the viewpoint of on-line processing for big data.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.558-565
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• 2000

SK-1080 is one of the newly developed orally active nonpeptide angiotensinII $AT_1-receptor$ antagonist that selectively acts at $AT_1$ receptor with high affinity. The cardiac effect on ischemia/reperfusion injury of SK-1080 was compared with those of losartan, a prototype of this class, in isolated rat hearts. Isolated perfused rat heart was pretreated with drug for 10 min and then subjected to global ischemia for 30 min followed by reperfusion with- or without drug for 30 min. The possible additive effect of SK-1080 on the platelet aggregation and coagulation in human blood was also studied. We investigated whether SK-1080 effects the platelet aggregation induced by ADP, a platelet agonist partially dependent on $thromboxaneA_2$. The clotting times in the prothrombin time (PT) and activated partial thromboplastin time (APTT) were also examined in human plasma in vitro as coagulation screening test. SK-1080 improved reperfusion function (LVDP, left ventricular developed pressure; PRP, rate-pressure product) in a dose-dependent manner. SK-1080 reduced ADP-induced platelet aggregation compared with vehicle but less than losartan, and did not affect clotting times.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.6
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• pp.689-694
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• 2014

DDoS attacks on MANET makes disable any node which support network function, cause critical results as a stopping of entire network service or separation to some parts. Packet aggregation, which gather some pieces of short length into a certain length of data, improves transmission performances on MANETs. In this paper, some effects on transmission performance of packet aggregation transmission be caused by DDoS Attacks are measured and analyzed in point of end-to-end level. MANET simulator, based on NS-2, is used for measurement end-to-end performances. MOS, connection rate, delay and packet loss rate is used as performance parameters. VoIP traffic is used for object service measurement. Finally, it is suggested that number of packet aggregation is more then 4 for keeping the transmission quality over MANETs under DDoS attacks.

• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.472-476
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• 2011

Hypercholesterolemia indirectly increases the risk of arterial and venous thrombosis by enhancing the ability of platelets to aggregate. Yacon (Smallanthus sonchifolius) is composed of fructooligosaccharides, proteins, minerals and phenolic compounds, and has potential benefits for the management of diabetes. This study investigated whether the consumption of yacon in the diet inhibits platelet aggregation under hypercholesterolemic conditions. Male New Zealand white rabbits were fed one of five dietary interventions: a normal control diet, 0.5% cholesterol diet, 0.5% cholesterol diet+a low dose of yacon (0.5 g/kg body weight given orally each day), 0.5% cholesterol diet+a high dose of yacon (2.5 g/kg body weight given orally each day), or a 0.5% cholesterol diet+lovastatin (2 mg/kg body weight given orally each day). After 8 weeks, blood was collected to measure the amount of collagen- and thrombin-induced platelets present. Yacon inhibited the platelet aggregation induced by low doses of agonists (0.5 ${\mu}g/mL$ collagen and 0.02 units/ml thrombin) in a concentration-dependent manner. In addition, yacon concentration-dependently inhibited collagen-induced arachidonic acid liberation. Moreover, n-hexane, chloroform and ethyl acetate fractions showed a marked and selective inhibition of the platelet aggregation induced by collagen, again in a dose-dependent manner. These fractions, especially that of chloroform, significantly suppressed platelet aggregation. The results of this study demonstrate that when yacon is added to a cholesterol-enriched diet, cholesterol-induced platelet aggregation returns to control levels. This may also be beneficial in preventing atherosclerosis and reducing risk factors for coronary artery disease and stroke.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.873-886
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• 1996

For better understanding the interrelationship of hemorrhage and aggregation mechanism, cyclopiazonic acid(CPA) known as promoting the aggregation of platelet, aflatoxin $B_1(AFB_1)$ inhibiting platelet aggregation were used as toxic mycotoxins in these studies. In order to investigate the potential role of prostaglandin metabolism on the platelet aggregation, a variety of prostaglandin metabolites such as $PGF_{2{\alpha}}$, $PGE_2$ and $TXB_2$ were measured in homogenized rabbit platelets by TLC and LSC. And the role of $Ca^{{+}{+}}$ on the platelet aggregation was investigated by flow cytometer. Finally, the morphological effects of mycotoxins on platelet were determined by transmission electron microscope. The results and conclusions obtained from these studies are: 1) CPA induced no changes but $AFB_1$ increased $PGE_2$ and $TXB_2$. 2) CPA promoted ADP, collagen, thrombin, A.A., and PAF-induced $Ca^{{+}{+}}$ release. $AFB_1$, however, decreased $Ca^{{+}{+}}$ level except collagen-induced $Ca^{{+}{+}}$ release. When the calcium blocker, verapamil, was used, CPA decreased thrombin-induced $Ca^{{+}{+}}$ release and increased collagen, ADP, PAF and A.A.-induced $Ca^{{+}{+}}$ release. $AFB_1$ in contrast decreased the all factors induced $Ca^{{+}{+}}$ release. 3) $AFB_1$ did not induce any ultrastructural changes except large vacuole formation in a few platelets. And CPA also did not induce any changes except moderate shape change, indicator of platelet activation. In conclusion, CPA promoted platelet aggregation by the increases of $Ca^{{+}{+}}$ release but had no changes in A.A. metabolites. Antiaggregating effects of $AFB_1$ may be due to decreases of $Ca^{{+}{+}}$ release and increases of $PGE_2$ and $PGF_{2{\alpha}}$ formation. These data provide the basis for the future study of mobilization and function of $Ca^{{+}{+}}$ in platelet aggregation.

• Nutrition Research and Practice
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• v.13 no.1
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• pp.64-69
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• 2019

BACKGROUND/OBJECTIVES: Alzheimer's disease is a neurodegenerative disease that induces symptoms such as a decrease in motor function and cognitive impairment. Increases in the aggregation and deposition of amyloid beta protein ($A{\beta}$) in the brain may be closely correlated with the development of Alzheimer's disease. In this study, the effects of an adzuki bean extract on the aggregation of $A{\beta}$ were examined; moreover, the anti-Alzheimer's activity of the adzuki extract was examined. MATERIALS/METHODS: First, we undertook thioflavin T (ThT) fluorescence analysis and transmission electron microscopy (TEM) to evaluate the effect of an adzuki bean extract on $A{\beta}_{42}$ aggregation. To evaluate the effects of the adzuki extract on the symptoms of Alzheimer's disease in vivo, $A{\beta}_{42}$-overexpressing Drosophila were used. In these flies, overexpression of $A{\beta}_{42}$ induced the formation of $A{\beta}_{42}$ aggregates in the brain, decreased motor function, and resulted in cognitive impairment. RESULTS: Based on the results obtained by ThT fluorescence assays and TEM, the adzuki bean extract inhibited the formation of $A{\beta}_{42}$ aggregates in a concentration-dependent manner. When $A{\beta}_{42}$-overexpressing flies were fed regular medium containing adzuki extract, the $A{\beta}_{42}$ level in the brain was significantly lower than that in the group fed regular medium only. Furthermore, suppression of the decrease in motor function, suppression of cognitive impairment, and improvement in lifespan were observed in $A{\beta}_{42}$-overexpressing flies fed regular medium with adzuki extract. CONCLUSIONS: The results reveal the delaying effects of an adzuki bean extract on the progression of Alzheimer's disease and provide useful information for identifying novel prevention treatments for Alzheimer's disease.