• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.63-73
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• 2008

RFID(Radio Frequency IDentification) system is an automated identification system that basically consists of tags and readers and Back-End-Databases. Tags and Readers communicate with each other by RF signal. As a reader can identify many tags in contactless manner using RF signal, RFID system is expected to do a new technology to replace a bar-code system in supply-chain management and payment system and access control and medical record and so on. However, RFID system creates new threats to the security of systems and privacy of individuals, Because tags and readers communicate with each other in insecure channel using RF signal. So many people are trying to study various manners to solve these problems against attacks, But they are difficult to apply to RFID system based on EPCglobal UHF Class-1 Generation-2 tags. Recently, Chien and Chen proposed a mutual Authentication protocol for RFID conforming to EPCglobal UHF Class-1 Generation-2 tags. we discover vulnerabilities of security and inefficiency about their protocol. Therefore, We analyze vulnerabilities of their protocol and propose an efficient mutual authentication protocol that improves security and efficiency.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.362-371
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• 2022

This study was conducted to analyze the fragrance characteristics of Cymbidium 'Saelbit' and 'Midan' according to floral organs. As test materials, full bloom flowers were divided into four organs: sepal, petal, labellum, and column. Using the gas chromatography (GC) based electronic nose, fragrance patterns, intensity, and volatile components were analyzed. Principle component analysis (PCA) and discriminant factorial analysis (DFA) plots by electronic nose data showed that volatiles of both cultivars have a distinct difference in fragrance patterns according to the floral organs, and the value of fragrance distance and pattern discrimination index (PDI) between samples was significantly high between control and sepals in both cultivars. Among the main fragrance components, several components including nootkatone were detected in both cultivars and all floral organs. However, few components such as decane were found in specific cultivar or floral organs. These results will provide useful information to select suitable materials with desired fragrance and to enhance the utilization of domestic Cymbidium cultivars. In addition, considering the recent negative perception of artificial ingredients and the growing demand for natural materials, continuous researches on scent properties of promising cultivars are required.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.4
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• pp.323-328
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• 1998

A field experiment was carried out to determine the effects of chemical and mechanical treatment at mowing on the field drying rate and hay quality of autumn oat (Avena sativa L.). The chemical drying agent/mower conditioner ($K_2CO_3$ 2%, conditioning, $K_2CO_3$ 2% + conditioning and control) were treated at different harvest stages (late boot, heading and bloom stage) for hastening hay manufacture in the autumn of 1996. After field dry, square bales were made by hay baler, and the dry matter(DM) loss and visual estimation of oat hay were evaluated after storing two months. In general, the field drying rate of oat was slow, regardless of harvest stage. Mechanical and chemical + mechanical treatment were effective, but the effectiveness of chemical alone was very low. With mower conditioning, the duration of field dry was shortened by 2 days compared with control. The DM loss of hay was higher at boot stage(51.4%) than at heading stage (21.1%), and the DM loss was reduced by mechanical and chemical + mechanical combined treatment. The visual score (leafiness, green color, odor and softness) of hay after storing was high in mechanical and chemical + mechanical, but the score by chemical alone was very low. The nutritive value (ADF, NDF, digestibility, and relative feed value) of hay was also high with treatment of mechanical and chemical + mechanical, but the quality by chemical alone was similar compared with control. In conclusion, mower conditioning can enhance the field drying rate of autumn oat, but the drying efficiency of the chemical drying agent was very low. However, it is suggested that hay-making of oat in autumn is very hard though using mower conditioner.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.170-177
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• 2017

This study was conducted to estimate the light pollution damage caused by night-break lighting in 'Kyoho' grapes. Night irradiation was performed every night for four hours (10 p.m. to 2 a.m.) from the full bloom to the harvest stage using red, blue, and white lamps as artificial light. Fruit yield, soluble solid content, anthocyanin content, and chlorophyll a content were affected by night irradiation. The soluble solid content of the control was $17.5^{\circ}Brix$, approximately $1^{\circ}Brix$ higher than the red ($16.4^{\circ}Brix$), blue ($16.2^{\circ}Brix$), and white light treated grapes ($16.3^{\circ}Brix$). The anthocyanin content of the skin was also higher in the control at $4.08{\mu}g{\cdot}cm^{-2}$ compared to the red ($3.14{\mu}g{\cdot}cm^{-2}$), blue ($2.47{\mu}g{\cdot}cm^{-2}$), and white ($2.82{\mu}g{\cdot}cm^{-2}$) light treated samples. On the other hand, the chlorophyll a content of the control was the lowest at $0.268{\mu}g{\cdot}cm^{-2}$ as compared with the red ($0.339{\mu}g{\cdot}cm^{-2}$), blue ($0.345{\mu}g{\cdot}cm^{-2}$), and white ($0.372{\mu}g{\cdot}cm^{-2}$) light treated samples. Considering that higher soluble solid contents, higher accumulation of anthocyanin, and lower chlorophyll a contents are factors involved in fruit maturation, night irradiation may delay fruit maturation and red light treatment may result in decreased yield. Our results confirmed that night-break lighting regardless of the wavelength provoked light pollution in 'Kyoho' grapes. Therefore, fruit maturation may be poor in the presence of artificial light, including streetlamps, in neighboring vineyards.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.346-362
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• 2021

A sediment control dam is an artificial structure built to prolong sedimentation in the main dam by reducing the inflow of suspended solids. These dams can affect changes in dissolved organic matter (DOM) in the water body by changing the river flow regime. The main DOM component for Yeongju Dam sediment control of the Naeseongcheon River was analyzed through 3D excitation-emission matrix (EEM) and parallel factor (PARAFAC) analyses. As a result, four humic-like components (C1~C3, C5), and three proteins, tryptophan-like components (C2, C6~C7) were detected. Among DOM components, humic-like components (autochthonous: C1, allochthonous: C2~C3) were found to be dominant during the sampling period. The total amount of DOM components and the composition ratio of each component did not show a difference for each depth according to the amount of available light (100%, 12%, and 1%). Throughout the study period, the allochthonous organic matter was continuously decomposing and converting into autochthonous organic matter; the DOM indices (fluorescence index, humification index, and freshness index) indicated the dominance of autochthonous organic matter in the river. Considering the relative abundance of cyanobacteria and that the number of bacteria cells and rotifers increased as autochthonous organic matter increased, it was suggested that the algal bloom and consequent activation of the microbial food web was affected by the composition of DOM in the water body. Research on DOM characteristics is important not only for water quality management but also for understanding the cycling of matter through microbial food web activity.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.211-215
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• 2011

This study aimed to determine optimum leaves per shoot in 'Campbell Early' grape through investigating changes of fruit quality after veraison 70~75 berries of first cluster and 35~40 berries of second cluster at 30 days after full bloom. Soluble solids content (SSC) increased dramatically during 28 days after veraison and afterwards it was stabilized. 15 leaves per shoot treatment showed fast increase of SSC from early veraison and reached to over 16.0oBx at 28 days after veraison. No considerable increase of SSC were occurred on either 5 or 0 leaves per shoot treatments after veraison. Titratable acidity (TA) was decreased continuously during 28 days of berry ripening in the all treatments. In 15 leaves per shoot treatment, TA decreased fast during first 7 days after veraison and continuously decreased to 0.5% by harvest time. While, 5 and 0 leaves per shoot treatments showed TA decrease slightly only at the early veraison. Hunter L and b values of 15 leaves per shoot treatment decreased fast during first 7 days of veraison, and gradually decreased by 14 days, whereas Hunter a value increased fast during the first 7 days from veraison. Total anthocyanin content in 15 leaves per shoot treatment increased fast from 7 days of veraison and the increase became slow after 28 days of veraison. Other treatments showed no significant difference from veraison to harvest time.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.233-240
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• 2011

We evaluated the changes of fruit quality factors and the incidence of physiological disorders during the periods of high temperature environment in 'Wonhwang' and 'Whasan' pears to determine appropriate harvest time for exportation. In 'Wonhwang' pears, the fruits harvested at 130 days after full bloom (DAFB) showed 31.3 and 17.6N of flesh firmness after 5 and 10 days after simulated marketing at $30^{\circ}C$, respectively, while those of the fruits harvested at 135 DAFB lowered to 16.7 or 6.9N, respectively. Whereas, 'Whasan' pear showed higher firmness during 14 days of high marketing condition than 'Wonhwang' pears which represented 30.4, 26.5 and 21.6N in the fruits harvested 145, 150 and 155 DAFB, respectively. Higher soluble solid contents and lower acidity values observed in the late harvested fruits in both cultivar along with increased marketing period at $30^{\circ}C$. Late harvested 'Wonhwang' pears showed higher respiration rate and ethylene production than early harvested ones, while those of 'Whasan' pears showed lower values regardless of fruit maturity which represented less than 50% of 'Wonhwang' pears. The incidence of physiological disorders such as internal browning, water soaking, flesh spot decay, core breakdown and pithiness appeared more severely in the fruits of 'Wonhwang' in accordance with the progress of high temperature marketing and fruit maturity. Whereas, those symptoms were occurred only after 14 days of prolonged marketing time in 'Whasan' pears. Consequently, it was needed to pay more attention to determine the ripeness when the fruits exported to the country with high temperature environment, especially in the fruits of 'Wonhwang' pears showing rapid quality loss and severe physiological disorders.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.35-45
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• 2018

The seaweed Ulva spp., which is frequently bloomed in coastal areas, have negatively affected on marine ecosystem and industrial activities. Therefore, many researches have been conducted to solve this problem in the worldwide. In this study, we carried out several experiments to develop the methods for effectively controlling Ulva growth through an alone or mixture application of chemical and temperature. Three chemical mixtures ($H_2O_2$+N-vanillylnonanamide; $H_2O_2$+nonanoic acid; $H_2O_2$+sodium citrate), those had a synergistic effect to the death of Ulva australis (ULAUS), were found out. On the other hand, the death of ULAUS was significantly enhanced and accelerated as some chemicals were briefly treated with warm water of $40^{\circ}C$ rather than $25^{\circ}C$, showing that peracetic acid 100 ppm, sodium percarbonate 100 ppm, and hydrogen peroxide 30 ppm has a better activity than that of sodium chlorite 200 ppm and menadione sodium bisulfite 4 ppm. In addition, a strong synergistic effect to the death of ULAUS thallus was also observed when the sodium citrate 1,000 ppm (pH 3.0) or acetic acid 200 ppm (pH 3.5) solution prepared in f/2 medium were treated in a short time at $40^{\circ}C$. However, an additive effect was only appeared as pH values of their solutions were increased to 8.0. Taken together, It seemed that our results could be developed as one of an eco-friendly practical measures useful for alleviating Ulva bloom in the future.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.31-41
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• 2011

To optimize the natural chemical agents against nuisance phytoplankton, we examined algal removal activity (ABA) of Plant-Mineral Composite (PMC), which already developed by our teams (Kim et al., 2010), on various conditions. The PMC are consisted of extracted-mixtures with indigenous plants (Camellia sinensis, Quercusacutissima and Castanea crenata) and minerals (Loess, Quartz porphyry, and natural zeolite), and characterized by coagulation and floating of low-density suspended solids. A simple extraction process was adopted, such as drying and grinding of raw material, water-extraction by high temperature-sonication and filtering. All tests were performed in 3 L plastic chambers varying conditions; six different concentrations ($0{\sim}1.0\;mL\;L^{-1}$), six light intensities ($8{\sim}1,400\;{\mu}mol\;m^{-2}s^{-1}$), three temperatures ($10{\sim}30^{\circ}C$), four pHs (7~10), five water depths (10~50 cm), and three different waters dominated by cyanobacteria, diatom, and green algae, respectively. Results indicate that the highest ABA of PMC was seen at $0.05\;mL\;L^{-1}$ in treatment concentrations, where showed a reduction of more than 80% of control phytoplankton biomass, while $1,400\;{\mu}mol\;m^{-2}s^{-1}$ in light intensity (>90%), $20{\sim}30^{\circ}C$ temperature (>60%), 7~9 in pH (>90%), below 50 cm in water depth (>90%), and cyanobacterial dominating waters (>80%), respectively. Over the test, ABA of PMC were more obvious on the algal biomass (chlorophyll-${\alpha}$) than suspended solids, suggesting a selectivity of PMC to particle size or natures. These results suggest that PMC agents can play an important role as natural agents to remove the nuisant algal aggregates or seston of eutrophic lake, where occur cyanobacterial bloom in a shallow shore of lake during warm season.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.399-405
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• 2011

In this study, we evaluated the fruit quality indices and the incidence of physiological disorders of Korean new pear cultivar 'Whasan' to determine appropriate harvest time for exportation and to enhance storability and shelf-life of the fruits during simulated exportation and extending market environment under different temperature conditions. In the experiment of simulated exportation headed for North America including Canada and U.S.A., the fruits transported at $1^{\circ}C$ showed less weight loss than those of $5^{\circ}C$. Market temperature appeared as a key factor for keeping freshness of exported pear fruits rather than transportation temperature. Quality factors such as high flesh firmness and low incidence of fruit rot and physiological disorders including core breakdown and pithiness were attained at the fruits maintained at $18^{\circ}C$ when we compared with $25^{\circ}C$. The fruits of harvested early maturity at 135 day after full bloom showed 28.6 N of flesh firmness when the fruits stored at $1^{\circ}C$ of transportation and $18^{\circ}C$ of market temperature, while the fruits progressed $5^{\circ}C$ of transportation and $25^{\circ}C$ of market temperature dropped to 24.2 N during 30 days of shelf life. Also, a high incidences of physiological disorders and of fruit decay rates were obvious in the fruits distributed at $25^{\circ}C$ were observed approximately two times higher than the those of $18^{\circ}C$. Therefore, temperature management during marketing resulted as an important point for maintaining fruits quality in the process of pear fruit exportation.