• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.251-254
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• 2011

In a WLAN, the data reception rate of a user station depends not only on the received signal strength (RSS) from an AP (Access Point) but also on the contention level of the AP. However, since only the RSSs measured at the physical layer have been used for a station to select an AP to associate with, the station may not satisfy the minimum quality requirements necessary for a seamless IPTV service. Thus, in this paper, we propose an AP selection method to support quality requirements of the IPTV service in a wireless LAN without modifying the IEEE 802.11 standard. A user station keeps monitoring a contention level of APs around it and a quality of an ongoing IPTV service. If the quality deteriorates below a threshold, the station reassociates with another AP having the least load so that the ongoing IPTV program is played without disruption.

• Membrane Journal
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• v.22 no.4
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• pp.235-242
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• 2012

Ammonium perchlorate (AP) is primarily derived from the process of liquid incineration treatment when dismantling a solid rocket propellant. A series of batch dead-end nanofiltration (NF) and reverse osmosis (RO) membrane experiments were conducted to explore the retention mechanisms of AP under various hydrodynamic and solution conditions. Low levels of silicate type of siloxane had been detected through the GC/MS and FTIR analysis of liquid solutions extracted from solid ammonium perchlorate composite propellant (APCP). It is indicated that NF/RO membranes fouling in the presence of APCP was mainly attributed to the AP interactions because the concentration of silicate type of siloxane was negligible compared to that of AP. The osmotic pressure of AP was presumably resulted in the flux declines ranging from 13 to 17% in the case of the application of low-pressure (551 and 896 kPa for NF and RO) compared to those in application of high-pressure. The retention of AP by NF/RO membranes significantly varied from approximately 10 to 70% for NF and 26 to 87% for RO, depending on the operating and solution water chemistry conditions. The results suggested that retention efficiency of AP was fairly increased by reducing concentration polarization (i.e. application of low-pressure and stirring speed of 600 rpm) and increasing the pH of a solution. The result of this study was also consistent with the previous modeling of 'solute mass transfer of NF/RO membranes' and demonstrated that hydrodynamic and solution water chemistry conditions are to be a key factor in the retention of AP by NF/RO membranes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.593-597
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• 2004

This study was conducted to investigate the quality characteristics of liquid calcium acetate (LCAs) and solid calcium acetate (SCAs), Br-LCA, Pe-LCA and Ap-LCA as liquid form, Br-SCA, Pe-SCA and Ap-SCA as solid form. Calcium acetate was prepared by reacting of vinegars [brown rice (Br), persimmons (Pe) and apple (Ap)] and ash of black snail in order to obtain natural water soluble calcium resources. The pHs of the vinegars for preparing calcium acetate (CA) were the range of 2.34 ∼ 3.06, and the contents of the ash of black snail which reacted to 100 mL of the vinegars were 20.43∼23.50 g. The yields of solid CAs from 100 mL of the vinegars were 11.02∼13.01 g. The colors of liquid and solid CAs were light yellow in Ap-LCA and Ap-SCA, brown in Br-LCA and Br-SCA, dark brown in Pe-LCA and Pe-SCA. Calcium contents of Br-LCA, Pe-LCA and Ap-LCA were 3.02, 2.06 and 2.30% (w/v), and those of Br-SCA, Pe-SCA and Ap-SCA were 27.15, 16.31 and 19.48% (w/w), respectively. The solubilities of the solid CAs were 36.82 ∼ 39.92% (w/v) in distilled water, 32.05 ∼ 39.04% (w/v) in Soju, 13.12 ∼ 18.65% (w/v) in thick soysauce, 38.35 ∼ 38.90% (w/v) in ionic beverage, 33.47 ∼ 35.58% (w/v) in yoghurt, while the solid CAs formed the curds in soymilk and milk. The sour and bitter taste of the CAs were lower, while the astringent taste, fishy flavor and savory taste were higher than those of standard CA.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.7-12
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• 1999

The effects of antioxidants, ascorbyl palmitate (AP), ${\alpha}-tocopherol\;({\alpha}-Toc)$, BHA and ascorbyl $palmitate+{\alpha}-tocopherol\;(AP+{\alpha}-Toc)$ have been investigated on lipid peroxide formations in tallow immediately and during storage at $50^{\circ}C$ after gamma irradiation with the dose of $1{\sim}10kGy$. Immediately gamma irradiation greatly increased the initiative oxidation of tallow as was expected. But antioxidants were found to be greatly effective in minimizing the radiation-induced peroxidation of tallow and their antioxidative activities were $AP>BHA>AP+{\alpha}-Toc>{\alpha}-Toc$. Especially, AP showed greater antioxidative activity of initiate-oxidation than that of any other antioxidant. Oxidation of tallow during storage at $50^{\circ}C$ after irradiation induced the accelate of autoxidation. But the additions of antioxidants inhibited formation of peroxide. Their antioxidative activities were $BHA>AP+{\alpha}-Toc>{\alpha}-Toc>AP$. Especially $AP+{\alpha}-Toc$ mixture was not significantly different from BHA (p>0.05).

• The Plant Pathology Journal
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• v.18 no.5
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• pp.259-265
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• 2002

Apple mosaic virus (ApMV), a member of the genus Ilarvirus, was detected and isolated from diseased 'Fuji' apple (Malus domestica) in Korea. The coat protein (CP) genes of two ApMV strains, denoted as ApMV-Kl and ApMV-K2, were amplified by using the reverse transcription and polymerase chain reaction (RT-PCR) and were analyzed thereafter. The objectives were to define the molecular variability of genomic information of ApMV found in Korea and to develop virus-derived resistant gene source for making virus-resistant trans-genic apple. RT-PCR amplicons for the APMVS were cloned and their nucleotide sequences were determined. The CPs of ApMV-Kl and ApMV-K2 consisted of 222 and 232 amino acid residues, respectively. The identities of the CPs of the two Korean APMVS were 93.1% and 85.6% at the nucleotide and amino acid sequences, respectively. The CP of ApMV-Kl showed 46.1-100% and 43.2-100% identities to eight different ApMV strains at the nucleotide and amino acid levels, respectively. When ApMV-PV32 strain was not included in the analysis, ApMV strains shared over 83.0% and 78.6% homologies at the nucleotide and amino acid levels, respectively. ApMV strains showed heterogeneity in CP size and sequence variability. Most of the amino acid residue differences were located at the N-termini of the strains of ApMV, whereas, the middle regions and C-termini were remarkably conserved. The APMVS were 17.(1-54.5% identical with three other species of the genus Ilarviyus. ApMV strains can be classified into three subgroups (subgroups I, II, and III) based on the phylogenetic analysis of CP gene in both nucleotide and amino acid levels. Interestingly, all the strains of subgroup I were isolated from apple plants, while the strains of subgroups II and III were originated from peach, hop, or pear, The results suggest that ApMV strains co-evolved with their host plants, which may have resulted in the CP heterogeneity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.497-505
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• 2015

Existing Wi-Fi networks require users to follow network settings of the AP (Access Point), resulting in inconveniences for users, and the password of the AP is shared by all users connected to the AP, causing security information leaks as time goes by. We propose, in this work, a personalized secure Wi-Fi network, in which each user is assigned her own virtual Wi-Fi network. One virtual Wi-Fi per user makes the user-centric network configuration possible. A user sets a pair of her own SSID and password on her device a priori, and the AP publishes its public key in a suitable way. The AP also maintains an open Wi-Fi channel, to which users can connect anytime. On user's request, the user device sends a connection request message containing a pair of SSID and password encrypted with the AP's public key. Receiving the connection request message, the AP instantiates a new virtual AP secured with the pair of SSID and password, which is dedicated to that single user device. This virtual network is securer because the password is not shared among users. It is more convenient because the network adapts itself to the user device. Experiments show that these advantages are obtained with negligible degradation in the throughput performance.

• Journal of Life Science
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• v.31 no.8
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• pp.736-744
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• 2021

Artemisia princeps Pampanini is an herbal medicine widely used to immune function-related diseases, such as anti-oxidative, anti-inflammatory, and antibacterial agents. In this study, we investigated the anti-inflammatory effects of AP extract and underlying mechanisms were evaluated in RAW 264.7 cells. The effects of AP extract were also studied in a complete Freund's adjuvant (CFA)-induced arthritis and lipopolysaccharide (LPS)-induced inflammation mouse model. In RAW 264.7 cells, AP extracts significantly inhibited the LPS-induced nitric oxide (NO) production and inducible NO synthase and cyclooxygenase-2 protein expression. The LPS-induced phosphorylation of mitogen-activated protein kinases and nuclear factor-κB was also significantly blocked by AP extract in RAW 264.7 cells. Oral administration of AP extract suppressed the increase in mouse paw edema and spleen index compared to CFA-treated mice group. Histologically, the infiltration of inflammatory cells was increased in cartilage and synovium in the CFA-treated mouse group, whereas it was suppressed in the AP extract-administered group. Furthermore, AP extract treatment significantly reduced the inflammatory cytokine, tumor necrosis factor-α, levels in CFA and LPS-treated mouse. In conclusion, the anti-inflammatory and anti-arthritis effect of AP extract was confirmed in both in vitro and in vivo models, suggesting that Artemisia princeps Pampanini may be a candidate material for arthritis treatment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.1-6
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• 2006

This paper proposes association algorithm using load balancing for efficient AP selection under environment of wireless local area network(WLAN). Our scheme measures arrival time of association information when establishing the connection between access points and access terminal, analyzes the load condition of AP, and applies load balancing. AT selects and sets up low traffic AP by measuring traffic of connected access terminal, which can prevent over-franc of access points under hotspot environment that users access simultaneously. According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

• Speech Sciences
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• v.14 no.1
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• pp.37-62
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• 2007

The current study examines the role of post-lexical tonal patterns of a prosodic phrase in word segmentation. In a word spotting experiment, native Korean listeners were asked to spot a disyllabic or trisyllabic word from twelve syllable speech stream that was composed of three Accentual Phrases (AP). Words occurred with various post-lexical intonation patterns. The results showed that listeners spotted more words in phrase-initial than in phrase-medial position, suggesting that the AP-final H tone from the preceding AP helped listeners to segment the phrase-initial word in the target AP. Results also showed that listeners' error rates were significantly lower when words occurred with initial rising tonal pattern, which is the most frequent intonational pattern imposed upon multisyllabic words in Korean, than with non-rising patterns. This result was observed both in AP-initial and in AP-medial positions, regardless of the frequency and legality of overall AP tonal patterns. Tonal cues other than initial rising tone did not positively influence the error rate. These results not only indicate that rising tone in AP-initial and AP_final position is a reliable cue for word boundary detection for Korean listeners, but further suggest that phrasal intonation contours serve as a possible word boundary cue in languages without lexical prominence.

• Speech Sciences
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• v.15 no.1
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• pp.7-23
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• 2008

This paper investigates tonal patterns of the prosodic constituents of an AP and a PWD in Korean and their relation with the morphological/syntactic structure. Specifically, this paper asks the following questions: First, if there are more than one PWD in an AP, how is each PWD specified in terms of tones? Secondly, in case that there is only one PWD in an AP that consists of several morphemes, is there any preference of the association between tones and the morphemes that constitute that PWD? Thirdly, if an AP dominates a PWD and if a PWD contains at least one morpheme of the lexical category, it follows that an AP should contain at least one morpheme of the lexical category. Can this be verified with the experimental data? In order to answer these questions, Experiment I and II were conducted with the target material consisting of a stem and suffixes that varied in length. The results of this preliminary test show that as the number of syllables in the target material increases, the more number of an AP tonal pattern occurs in it and as a result, in some cases, an AP consisting of suffixes only may occur.