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The Effect of Decentralized Rainwater Tank System on the Reduction of Peak Runoff - A Case Study at M Village - (빗물저류조의 분산배치에 따른 첨두유출 저감효과 분석 - M 마을 사례 -)

  • Han, Moo-Young;Kum, So-Yoon;Mun, Jung-Soo;Kwak, Dong-Geun
    • Journal of Korea Water Resources Association
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    • v.45 no.1
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    • pp.65-73
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    • 2012
  • Recently climate change and increase of surface runoff caused the urban flooding. Traditional way of dealing with urban flooding has been to increase the sewer capacity or construction of pumping stations, however, it is practically almost impossible because of time, money and traffic problems. Multipurpose DRMS (Decentralized Rainwater Management System) is a new paradigm proposed and recommended by NEMA (National Emergency Management Agency) for both flood control and water conservation. Suwon City has already enacted the ordinance on sound water cycle management by DRMS. In this study, a flood prone area in Suwon is selected and analysis of DRMS has been made using XP-SWMM for different scenarios of RT installation with same total rainwater tank volume and location. Installing one rainwater tank of 3,000$m^3$ can reduce the peak flow rate by 15.5%. Installing six rainwater tanks of 500$m^3$ volume in the area can reduce the peak flow rate by 28%. Three tanks which is concentrated in the middle region can reduce peak rate more than evenly distributed tanks. The method and results found from this study can be used for the design and performance prediction of DRMS at a flood prone area by supplementing the existing sewer system without increase of the sewer capacity.

Influence of Carbonation for Chloride Diffusion in Concrete (탄산화 복합환경시 염소이온 확산에 관한 연구)

  • Oh Byung-Hwan;Lee Sung-Kyu;Lee Myung-Kue;Jung Sang-Hwa
    • Journal of the Korea Concrete Institute
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    • v.17 no.2 s.86
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    • pp.179-189
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    • 2005
  • Corrosion of steel due to chloride attack is a major concern in reinforced concrete structures which are located in the marine environments. In this case, Fick's 2nd law has been used for the prediction of chloride diffusion related with service life of concrete structures. However, those studies were confined mostly to the single deterioration due to chloride only, although actual environment is rather of combined type. The purpose of the present study is, therefore, to explore the influences of carbonation to chloride attack in concrete structures and to investigate the validity of Fick's law to chloride attack combined carbonation. The test results indicate that the chloride ion profiles from Fick's law using the diffusion coefficient of immersion tests is not reflected the effect of separation of chloride ions in carbonation region but valid in sound region in case of combined action. On the other hand, the chloride ion profiles from Fick's law using the diffusion coefficient of Tang and Nilsson's method coincide with test results under dry-wet condition but not under combined condition. The results of present study may Imply that the new method for the measurement of diffusion coefficient is required to predict the chloride ion profiles in case of combined action at early.

Development of Biotope Evaluation Indexes for Improving Bird Diversity (조류 다양성 확보를 위한 비오톱 평가지표개발)

  • Chae, Jin-Hwak;Koo, Tae-Hoe
    • Journal of Environmental Policy
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    • v.4 no.1
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    • pp.113-127
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    • 2005
  • This study was aimed at developing an application method of biotope evaluation indexes to secure bird diversity on urban biotope that has high intensity of land use. The main purpose of the study was to plan the effective restoration method of sound urban biotope from the ecological aspects after evaluating the relationship between the biotope evaluation indexes. The biotope area, number of insect species, distance from adjacent road, biotope area index were surveyed on each designated site in order to analyze the evaluation indexes that influenced bird diversity in urban biotope. The analysis of the relationship between biotope evaluation. indexes showed the following results number of bird species and number of insect species > number of bird species and biotope area index > number of insect species and biotope area index, that is, the number of insect species and biotope area index had a specific effect on the bird diversity. The equation derived from the above result is 'number of bird species = 6.124 $\times$ biotope area index + 0.095 $\times$ number. of insect species - 1.197' ($R^2=0.716$, F=27.743, P<0.001). Therefore, even a small area can be helpful for promoting bird diversity in the urban area if the biotope area index and diversity of vertical landscape for insects are maintained.

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Weldability with Process Parameters During Fiber Laser Welding of a Titanium Plate (I) - Effect of Type and Flow Rate of Shielding Gases on Weldability - (티타늄 판재의 파이버 레이저 용접시 공정변수에 따른 용접특성 (I) - 실드가스 종류 및 유량에 따른 영향 -)

  • Kim, Jong Do;Kim, Ji Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.12
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    • pp.1047-1053
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    • 2016
  • In this study, welding of pure titanium was carried out by using a continuous wave fiber laser with a maximum output of 6.3 kW. Because brittle regions form easily in titanium as a result of oxidation or nitriding, the weld must be protected from the atmosphere by using an appropriate shielding gas. Experiments were performed by changing the type and the flow rate of shielding gases to obtain the optimal shielding condition, and the weldability was then evaluated. The degree of oxidation and nitriding was distinguished by observing the color of beads, and weld microstructure was observed by using an optical microscope and a scanning electron microscope. The mechanical properties of the weld were examined by measuring hardness. When the weld was oxidized or nitrified, the bead color was gray or yellow, and the oxygen or nitrogen content in the bead surface and overall weld tended to be high, as a result of which the hardness of the weld was thrice that of the base metal. A sound silvery white bead was obtained by using Ar as the shielding gas.

EFFECT OF RESIN SEALANTS ON THE REDUCTION OF MICROLEAKAGE IN COMPOSITE RESTORATIONS (복합레진 수복물의 미세누출 감소를 위한 레진 전색제의 효과)

  • Cho Young-Gon;Kim Mun-Hong;Lee Myung-Goo
    • Restorative Dentistry and Endodontics
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    • v.31 no.4
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    • pp.282-289
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    • 2006
  • The purpose of this study was to compare the ability of three resin surface sealants to prevent microleakage in Class V composite resin restorations. Forty Class V cavities with the occlusal margin in enamel and gingival margin in dentin were prepared on the buccal surfaces of sound extracted molars, and restored with composite resin. Restorations were randomly assigned into one of four equal groups (n = 10): a control group, without resin sealing, and three experimental groups in which margins were sealed with Fortify Plus, Biscover and Permaseal, respectively. Specimens were thermocycled, immersed in a 2% methylene blue solution for 4 hours, sectioned longitudinally, and observed the leakage at the occlusal and gingival margins. The result was analyzed using Kruskal-Wallis test, Mann-Whitney test and Wilcoxon signed rank test. In conclusion, the ability to reduce microleakage at occlusal margins was similar in all of three sealants. However at gingival margin, it depended on the type of used resin surface sealant. At gingival margin. control and Fortify Plus group showed statistically higher microleakage than PermaSeal group. and Fortify Plus group also showed higher microleakage than BisCover group (p < 0.05).

Effects of interactivity and usage mode on user satisfaction, usefulness, and intetion to use in text information presentation in mobile environment (모바일 환경에서의 텍스트 표현 방식의 상호작용성과 사용모드가 사용자의 만족도, 유용성, 사용의도에 미치는 영향)

  • Baek, Hyunji;Lee, Sangwon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2017.10a
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    • pp.223-226
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    • 2017
  • With the development of information technology, users are provided with information they want through mobile device in various situations. When users communicate with information, there is interaction through gesture activities such as tapping and experience in the process. Experience through interaction in mobile affect the user's psychology. This is important because it is related to the behavior of the user in the future. Various types of information presentation methods have been researched in mobile environment. However, there are more research focusing on functional interactivity. The purpose of this study is to investigate the effect of interaction and usage mode on satisfaction, usefulness, and intention to use for sound text presentation that is user-centered. As variables for my study, there are two factors which are interactivity and usage mode. The interactivity type is composed of two ways that are: High and Low depending on modality and message interactivity; and the usage mode is composed of Action mode and Goal mode depending on whether user has a task or not. The experimental design is $2{\times}2$. The same content is provided in (a) only Modality interactivity, and (b) Modality and Message interactivity are provided. Depending on usage mode, (a) Action mode is processed without a specific task, and (b) Goal mode is performed with a specific task to participants. The experimental study demonstrated that there is a difference in satisfaction, usefulness, and intention to use depending on the difference of interaction and usage mode when providing information in mobile environment. The results of this study are summarized as follows: interaction and usage mode have significant influence on mobile user's satisfaction, usefulness, intention to use.

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Evaluation on Noise Characteristics by Field Application of Improved Rumble Strip (개선된 럼블스트립의 현장적용에 따른 사후 소음특성 평가)

  • An, Deok-Soon;Suh, Young-Chan;Son, Hyeon-Jang;Lee, Jae-Jun;Eom, Byeong-Sik
    • International Journal of Highway Engineering
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    • v.15 no.6
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    • pp.33-39
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    • 2013
  • PURPOSES : This research investigates traffic noise characteristics as change the transverse rumble strips shape from rectangular to cylinder at toll plaza of highway. METHODS : The traffic noise was investigated at two different places at toll plaza of highway. One is modified grooving, another is employed cylinder shape of TRS instead of rectangular shape of TRS. A measurement of traffic noise was conducted at same location and time period. The traffic volume information was gotten from office of highway office and vehicle speed was measured by speed measuring device. The traffic noise measurement was conducted from 13:00 to 23:00 and by pass-by method. Also, the traffic noise was measured behind noise barrier. Various distance from noise barrier(7.5m, 30m, 50m) and different heights(1.2m, 3m, and 5m) were parameter for measurement of traffic noise in this study. RESULTS : The class 1 vehicle was contributed from traffic volume which was increased 1,500. However, the distribution of traffic speed didn't change compare to previous investigated period. From this study, It was found that the external traffic noise was changed as function of geometric shape of TRS. The external noise from modified grooving was less than 1.2dB(A) of the current TRS. A difference of traffic noise was 20dB(A) before and after barrier. It came from a noise barrier effect as reduction of traffic noise. According to investigate a traffic noise distribution near barrier, there is similar noise characteristic as function of height at 7.5m distance from noise barrier. Also, There is no different traffic noise between 30m and 50m from source of the noise of sound barrier. CONCLUSIONS : Based on this traffic noise investigation result, there is a clear characteristic difference as changed TRS shape. The traffic noise was reduced by changed TRS shape. Specially, traffic noise was decreased although the traffic volume was increase for same investigation time and period. It is implied that cylinder type of TRS significantly reduces the traffic noise. The specification of various TRS will be studied in the future.

Nasalance Changes in Nasal Disease Patients after Nasal Cavity Operation (비질환 환자에서 비강수술 후 비음도 변화)

  • Lee, Jae-Hoon;Kim, Joo-Yeon;Lee, Kang-Dae;Kim, Seung-Tae;No, Yong-Hyeon;Kim, Kyung-A;Seo, Yun-Suk
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.21 no.2
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    • pp.128-132
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    • 2010
  • Background and Objectives : This study was designed to examine the effect of nasal cavity surgery on voice in terms of nasalance by using subjective test, Visual analogue scale (VAS) and Nasometer and compare the pre op and post op results among patiets with nasal cavity disease. Materials and Method : From April 2009 to November 2009, data of thirty one patients who underwent nasal cavity surgery were prospectively evaluated. 24 males and 7 females with age range between 12 years to 80 years old (average 34 years old) were chosen. VAS was questioned to patients group before, after 1 week, after 1 month, and after 3 months from the surgery. Nasometer, was also conducted. Results: After the surgery symptoms like nasal obstruction, mouth breath, snoring, and sleep apnea were all improved. Improvements for nasal obstruction and mouth breath were observed statistically in post operative day (POD) 1 month and POD 3 months. Also snoring was improved statistically in POD 1 month. Objective nasalance test showed increases in a single and double vowel for POD 3 months. Only /je/ sound statistically-significant increased in all post operative periods. Nasalance increase were observed in other test results. Conclusion : All the symptoms are improved after nasal cavity surgery. Also there are some nasalance changes during whole period of study and return to the pre operative state in POD 3 months. Therefore, patients must be warned and understood about nasalance changes, and surgeons need to aware of various facts, which can affect voice changes before the surgery.

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Postharvest Handling and Marketing Management for Making High Salability of Sweetpotatoes (상품성 제고를 위한 고구마 수확 후 관리 및 출하기술)

  • Jeong, Byeong-Choon
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2001.06a
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    • pp.51-64
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    • 2001
  • The qualities including taste of sweetpotato stored during the winter which can display in the spring market in Korea are affected by availability of storage for the roots. In order to make high storage availability of sweetpotato, the postharvest handlings should be done thoroughly from the moment of harvest until shipping them to the market. A lot of procedures that must be handled carefully for improving postharvest management are as follows; digging, trimming, gathering, putting in storage containers, carrying them from field to house, curing, storing, washing, drying, selecting marketable roots, packing and shipping to the market, etc.. Sweetpotatoes have a high moisture content, and a relatively thin and delicate skin, and are sensitive to chilling, so careless postharvest handling can lead to both quantitative and qualitative losses which may be extremely high in some circumstances. From now on research has concentrated on the improvement of postharvest conditions to increase yield and lower disease rates. Storage, which makes sweetpotatoes available through out the year, benefits both the producer and the consumer. Seven very important points must be needed in order to get the best quality marketable roots in the storing of sweetpotatos : $\circled1$The storage house must be clean and sanitary, $\circled2$The crop must be harvested before the first frost to avoid low-temperature injury, $\circled3$Particular care must be taken to avoid cutting, bruising, or other injuries of the sweetpotatoes during digging, picking up, grading, placing in containers, and moving to the storage house, $\circled4$Select sound, disease-free roots for storage $\circled5$Sweetpotatoes should be stored in properly stacked containers $\circled6$Cure immediately after harvest, preferably at 32∼33$^{\circ}C$ and 90 to 95 percent relative humidity for 4 to 7 days, After curing the temperature should be reduced to 13$^{\circ}C$ to 16$^{\circ}C$ by ventilating the storage with outside air. $\circled7$Store at 12$^{\circ}C$ to 14$^{\circ}C$ and a relative humidity of 80 to 85 percent. Storage houses should be located on suitable sites and should be tightly constructed and insulated so that temperature and humidity will be uniform. Sweetpotatoes are usually not washed and graded, and lately sometimes washed, graded, waxed, before being shipped to market. Consumer packaging of sweetpotatoes in paper boxes(10-15kg) or film bags is done mainly to aid marketing. The shelf life of washed roots in consumer packs in only 1 to 2 weeks. Weight loss of roots during marketing is much less in perforated film bags than in mesh and paper bags. Perforation of 0.8 to 1kg polyethylene bags with about six 6mm holes is essential ; to lower the internal relative humidity and avoid excessive sprouting, rooting, and dampness. Development and use of better postharvest handling with good storage facilities or marketing methods can minimize sweetpotate losses and has an effect of indirectly increasing productivity and farmer’s income.

Perception of Japanese word-initial stops by native listeners (모어청자에 의한 일본어 어두 폐쇄음의 지각)

  • Byun, Hi-Gyung
    • Phonetics and Speech Sciences
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    • v.13 no.3
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    • pp.53-64
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    • 2021
  • It is known that the voicing contrast for Japanese word-initial stops is primarily realized as differences in the voice onset time (VOT). However, recent studies have reported that voiced stops are more often produced with a positive VOT than with a negative VOT among the younger generation nationwide. It is also known that post-stop F0 is associated with the stop contrast, but the degree of F0 use differs from region to region. This study explores whether the difference in post-stop F0 functions as a perceptual cue to the stop contrast along with VOT. Fifty-five college students who are native listeners from four different regions participated in two or three perception tests. The results show that VOT is a primary cue to the voiced-voiceless distinction of word-initial stops, but that the effect of post-stop F0 on the stop contrast is marginal. The post-stop F0 is involved in perception only when VOT is ambiguous, such that a sound with high F0 is more often perceived as a voiceless stop, but not vice versa. The results of this study indicate that the acoustic parameters associated with the stop contrast are not the same in production and perception, and suggest that other factors such as context, which is not an acoustic characteristic, may also be involved in the stop contrast.