• Environmental Analysis Health and Toxicology
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• v.15 no.1_2
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• pp.19-29
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• 2000

Acetanilide may be released into the environment through air and wastewater from its production and use sites as an intermediate in the synthesis of pharmaceuticals and dyes. Acetanilide is biodegraded rapidly under aerobic conditions and decomposed by indirect photolysis in the presence of OH radicals. An estimated bioconcentration factor of 4.5 suggests that bioaccumulation in aquatic organisms is low. Ecotoxicological data on acetanilide exist on acute toxicity to fishes of 4 species only. According to the EUSES system, the lowest PNEC (Predicted no effect concentration) in fishes is 0.01 mg/1 and PEC (Predicted environmental concentration) for surface water on a regional scale is 9.1$\times$10$\^$－5/mg/l as the worst case. RCR (Risk characterization ratio) of acetanilide for surface water on a regional scale was estimated as 9.1$\times$10-3, which is safe enough for fishes, RCR on a local basis slightly exceeds the value 1 in water and sediment; that is, 1.3 and 1.6, respectively, which suggests the existence of ecotoxicological risk at the vicinity of the manufacturing site. For the refinement of environmental risk assessment on acetanilide, more data should be collected regarding prolonged fish toxicity, acute toxicity toward daphnia and algae. It is, therefore, recommended that acetanilide should be a candidate for further work to supplement the lacking data until it is proved to be safe in the ecotoxicological aspects.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.31 no.3
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• pp.140-149
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• 2018

Objectives : The aim of this study is to report the effect of herbal medicine and acupuncture on a breastfeeding woman's postpartum urticaria which was unresponsive to a 1st generation antihistamine and a topical steroid. Methods : Wheals and pruritus occurred to a 36-year-old breastfeeding woman 2 days after the parturition. Symptoms were unresponsive to about a week of systemic antihistamine and topical steroid treatments. GamiSamul-tang herbal decoction was administered three times a day for the first 21 days and twice a day for the next 10 days of the treatment. Acupuncture treatment was applied to 12 acupoints (both sides of LI04, LR03, ST36, LI11, SP10, SP6) for 15 minutes once a week, 5 times in total. The patient's symptom was evaluated with Weekly Urticaria Activity Scale (UAS7) and Visual Analogue Scale for Worst Pruritus within 24 hours ($VAS_{Pruritus}$) each time the patient visited out-patient department. Results : The scores of UAS7 and $VAS_{Pruritus}$ at the baseline were 38 and 8.2 respectively. 10 days after the herbal medicine and acupuncture treatment began, both decreased to 0 and wheal, pruritus, erythema didn't appeared again for the rest of the follow up periods. Conclusions : This study shows the possibility of using GamiSamul-tang and acupuncture to treat postpartum urticaria.

• Management & Information Systems Review
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• v.28 no.3
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• pp.69-98
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• 2009

This study investigates in-sample and out-of-sample predictive abilities of accruals and accruals components with respect to future cash flows using models developed by Barth et al.(2001). In tests, data collected fromda62 Korean KOSPI and KOSDAQ listed firms for ccr4-2007 are used. Results of in-sample prediction tests are similar with those of Barth et al.(2001). Their accrual components model is better than other three models(NI only model, CF only model and NI-total accruals model) in future cash flows predictive ability. That is, in the case of in-sample prediction, accrual components excluding amortization have additional information contents for future cash flows. But in out-of-sample tests, the results are different. The model including operational cash flows(CF only model) shows best out-of-sample predictive ability with respect to future cash flows among above four prediction models. The accrual components model of Barth et al.(2001) has worst out-of-sample predictive ability. The results are robust to sensitivity analyses. In conclusion, we can't find the evidence that accruals and accrual components have predictive ability with respect to future cash flows in out-of-sample prediction tests. This results are consistent with results of Lev et al.(2005), and inconsistent with the belief of accounting standards formulating organizations such as FASB and KASB.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.59-69
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• 2018

In this paper, we present a robust beamforming design to tackle the weighted sum-rate maximization (WSRM) problem in a multicell multiple-input multiple-output (MIMO) - non-orthogonal multipleaccess (NOMA) downlink system for 5G wireless communications. This work consider the imperfectchannel state information (CSI) at the base station (BS) by adding uncertainties to channel estimation matrices as the worst-case model i.e., singular value uncertainty model (SVUM). With this observation, the WSRM problem is formulated subject to the transmit power constraints at the BS. The objective problem is known as on-deterministic polynomial (NP) problem which is difficult to solve. We propose an robust beam forming design which establishes on majorization minimization (MM) technique to find the optimal transmit beam forming matrix, as well as efficiently solve the objective problem. In addition, we also propose a joint user clustering and power allocation (JUCPA) algorithm in which the best user pair is selected as a cluster to attain a higher sum-rate. Extensive numerical results are provided to show that the proposed robust beamforming design together with the proposed JUCPA algorithm significantly increases the performance in term of sum-rate as compared with the existing NOMA schemes and the conventional orthogonal multiple access (OMA) scheme.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.8
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• pp.8-16
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• 1999

In this paper, the performance of a hybrid DS/SFH-SS(direct-sequence/slow-frequency-hopped spread-spectrum) system with coherent BPSK modulation over Nakagami fading channel in the presence of multiple tone jamming is analyzed. Because the Nakagami m-distribution can describe not only Rayleigh fading but also more general fluctuations involving a specular component by adjusting the value of the fading index m. It is known that for m=1 corresponds to Rayleigh fading, for $1/2{\le}m{\le}1$ corresponds to the worst case fading condition, for m>1 corresponds to Rician fading, and for $m{\to}{\infty}$ corresponds to the nonfading condition. The bit error probability is derived over Nakagami model and numerical evaluations are presented for some combinations of system parameters. The results show that as m increases, the bit error probability is better. Also, at a low JSR(jamming-to-signal power ratio), a pure DS-SS system can achieve lower bit error probability than a hybrid DS/SFH-SS system. But at a high JSR, a hybrid DS/SFH-SS system is shown to be superior to a pure DS-SS system. Therefore, it is demonstrated that without increasing the total system bandwidth, the performance of a hybrid DS/SFH-SS is superior to that of a pure DS-SS system in the presence of multiple tone jamming.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.349-360
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• 2009

Purpose: As the esthetic demands of dental implant patients are increased, the demands of zirconia as implant abutment material are also increased. It has non-metalic color, good biocompatibility, high strength and high toughness. Even thought the advatage of zirconia abutment, there are a few studies about mechanical properties of zirconia abutment. This study evaluated the mecanical strength with compressive bending strength and endurance limit of implant-zirconia abutment assembly. Materials and Methods: Static and cyclic loading of implant-Zirconia abutment assembly were simulated under worst case condition according to ISO. Test groups were implants of external butt joint with straight regular diameter and angled regular diameter zirconia abutment, implant of external butt joint with narrow straight diameter zirconia abutment and implant of internal conical joint with straight narrow diameter zirconia abutment. All test group were evaluated the mecanical strength with compressive bending strength and endurance limit. After fatique testing, fracture surface were examined by SEM. Results: The compressive bending strengths exceed 927N. Regular diameter zirconia abutment were stronger than narrow diameter zirconia abutment(P<.05). The endurance limits ranged from 503N to 868N. Conclusion: Within the limitation of this study, zirconia implant abutment exceeded the estabilished values for maximum incisal biting forces reported in the literature.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.641-654
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• 1994

This study was executed to evaluate adaptability of dentin bonding agents to dentinal wall with measuring contraction gap on interface between cavity wall and composite resin by SEM study. 6 kinds of dentin bonding agents were investigated for this study : Gluma, Super Bond C & B, All bond 2, Scotchbond multipurpose, Scotchbond 2 and Clearfil photo bond. 30 of fresh extracted teeth were randomly selected and divided into 6 groups with each 5. The round shaped cavities with 3mm dia. and 1.5mm depth were prepared on cementoenamel junction of buccal surface of teeth. Dentin bonding agents were applied to cavity wall and then the composite resin was filled in the cavity. Specimens were sectioned longitudinally on buccal surface. Sectioned aspects of specimens were impressioned with rubber base materials and finally precise replica were made of epoxy resin poured in negative impression. Contraction gaps were examined on interface between cavity wall and composite resin under condition of 200 and 2000 magnification of SEM. The results were as follows. 1. There were no gap on interface between enamel and composite resin in all specimens, but gaps were mainly exhibited on apical side of lateral wall of dentin of cavity. 2. In Gluma, 2 cases of 5 specimens exhibited excellent adaptation to the cavity wall, indicating no gaps on interface between cavity wall and composite resin. The other specimens showed gaps with range of $0{\sim}15{\mu}m$ width. 3. In Super Bond C & B, gaps with range of $0{\sim}10{\mu}m$ width were mainly exhibited on apical side of lateral wall of dentin of cavity. 4. In All bond 2, all specimens showed the most exellent adaptation to cavity wall when compared to the other materials, indicating no gap interface between cavity wall and composite resin. 5. In Scotchbond multipurpose, gaps with range of $0{\sim}10{\mu}m$ width were locally located on cavity wall. 6. In Scotchbond 2, all specimens showed great amount of gap with range of $5{\sim}25{\mu}m$, indicating the worst adaptation to cavity wall compared to the other materials. 7. In Clearfil photo bond, 2 case of 5 specimens exhibited exellent adaptation to cavity wall, indicating no gap. the other specimens showed gap with range of $0{\sim}15{\mu}m$ width on inferface between cavity wall and composite resin.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.6
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• pp.548-556
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• 2015

The highly maneuverable fighter aircraft such as F-22, F-16 and F-15have the high maneuverability to maximize the combat performance, whereas the high maneuver characteristics might degrade the pilot's mission efficiency due to fatigue's increase by exposing him to the high gravity and, in the worst case, the pilot could face GLOC (Gravity-induced Loss Of Consciousness). The advanced aerospace company has applied the various technologies to improve the pilot's tolerance to the gravity acceleration, in order to prevent the pilot from entering the situation of the loss of consciousness. Especially, the Anti-G Suit(AGS) equipment to protect the pilot against the high gravity in flight could improve the mission success rate by decreasing the pilot's fatigue in the combat maneuver as well as prevent the pilot from facing GLOC. In this paper, a control algorithm is developed and verified to provide an optimal air pressure to AGS according to the gravity increase during the high performance maneuver. This result is expected, as the key technology, to contribute to the KF-X(Korean Fighter eXperimental), project in the near future.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.391-394
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• 2012

Exposure and risk assessment during mixing/loading of chlorpyrifos emulsifiable concentrate (EC, 20%) were carried out. Limit of detection and limit of quantitation were 0.02 and 0.1 ng, respectively. Calibration curve linearity and reproducibility were excellent. Recovery of chlorpyrifos from gloves was 72.3-103.4%. During mixing/loading procedure, average hand exposure amount of chlorpyrifos was 3.9 mg which is corresponding to 0.004% of total active ingredient in the prepared spray mixture. In calculation of MOS (Margin of Safety) for risk assessment, male Korean average body weight and AOEL (Acceptable Operator Exposure Level) were used. Nine events of mixing/loading procedure were assumed per day. And 75 percentile of 30 repetition (4.6 mg) was used as for the worst case. MOS was more than 1 for total repetition, indicating mixing/loading work was of least risk. However, MOS of individual repetition was examined, two cases were less than 1 suggesting careful work habit is essential in mixing/loading procedure.

• Journal of Environmental Impact Assessment
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• v.23 no.5
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• pp.353-363
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• 2014

The purpose of this study was to investigated the ELF-MF emission level of various environments such as 258 facilities near located to high voltage transmission lines and 120 high voltage transmission lines, 17 underground cable lines. In addition, ELF-MF reduction rate according to separation distance was calculated by using simulations. An appropriate separation distance showing below 4mG was at least 70m. In the case of the appropriate separation distance for 120 high voltage transmission lines, 154kV required 20m of separation distance and 345kV required 60m of separation distance. The simulation results showed that the appropriate separation distance showing below 4mG was 40m and 60m for overhead 154kV and 345kV respectively. To adjust the worst conditions considering the aspects of environmental impact assessment study and the electric power currents that will increase in the future, the appropriate minimum separation distance for HVTL is judged to be above 70m in this study. Thus, there is a need to establish the greenbelt or buffer zone within 70m so as to create an environment in which the receptors are not exposed and thereby eliminate the risk factors of ELF-MF against humans.