• Title/Summary/Keyword: arc measure

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Measurement of Skull Size on Computed Tomography Images for Developing a Bone Conduction Headset Suitable for the Korean Standard Head Size

  • Ku, Cheol Hyo;Kim, Soo Won;Kim, Ji Young;Paik, Seung Won;Yang, Hui Joon;Lee, Ji Hyeon;Seo, Young Joon
    • Korean Journal of Audiology
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    • v.24 no.1
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    • pp.17-23
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    • 2020
  • Background and Objectives: We aimed to measure the head dimensions on computed tomography (CT) images, to compare them to directly measured head dimensions, and to predict a new parameter of bone thickness for aiding bone conduction implant (BCI) placement. Subjects and Methods: We reviewed the facial and mandibular bone CT images of 406 patients. Their head sizes were analyzed using five parameters included in the 6th Size Korea project, and they were divided into age groups (ranging from the 10s to the 80s). We compared the head length, head width, sagittal arc, bitragion arc, and head circumference in the CT and Size Korea groups. We also added the parameter bone thickness for aiding BCI placement. Results: All the head size parameters measured using CT were significantly smaller than those measured directly, with head length showing the smallest difference at 7.85 mm. The differences in the other four parameters between the two groups according to patient age were not statistically significantly different. Bone thickness had the highest value of 4.89±0.93 mm in the 70s and the lowest value of 4.10±0.99 mm in the 10s. Bone thickness also significantly correlated with head width (p=0.038). Conclusions: Our findings suggested that the CT and direct measurements yielded consistent data. Moreover, CT enabled the measurement of bone sizes, including bone thickness, that are impossible to measure directly. CT measurements may complement direct measurements in the Size Korea data when used for developing bone conduction hearing devices (BCIs and headsets) for the Korean population.

A Study on Robust Pattern Classification of Lung Sounds for Diagnosis of Pulmonary Dysfunction in Noise Environment (폐질환 진단을 위한 잡음환경에 강건한 폐음 패턴 분류법에 관한 연구)

  • Yeo, Song-Phil;Jeon, Chang-Ik;Yoo, Se-Keun;Kim, Duk-Young;Kim, Sung-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.51 no.3
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    • pp.122-128
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    • 2002
  • In this paper, a robust pattern classification of breath sounds for the diagnosis of pulmonary dysfunction in noise environment is proposed. The feature parameter extraction method by highpass lifter algorithm and PM(projection measure) algorithm are used. 17 different groups of breath sounds are experimentally classified and investigated. The classification has been performed by 6 different types of combinations with proposed methods to evaluate the performances, such as ARC with EDM and LCC with EDM, WLCC with EDM, ARC with PM, LCC with PM, WLCC with PM. Furthermore, all feature parameters are extracted to 80th orders by 5th orders step, and all experiments are evaluated in increasing noise environments by degrees SNR 24dB to 0dB. As a results, WLCC which is derived from highpass lifter algorithm, is selected for the feature parameter extraction method. Pm is more robust than EDM in noisy environments to test and compare experimental results. WLCC with PM method(WLCC/PM) has a better performance in an increasing noise environment for diagnosis of pulmonary dysfunction.

A Study on the Fracture Toughness Characteristics of FCAW Weldment of Steel for Offshore Structures (해양 구조물용 강재 FCAW 용접부의 파괴인성 특성에 관한 연구)

  • Kang Sung-Won;Kim Myung-Hyun;Kim Yong-Bin;Shin Yong-Taek;Lee Hae-Woo
    • Journal of Welding and Joining
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    • v.22 no.6
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    • pp.57-63
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    • 2004
  • Fracture toughness is an important parameter in designing offshore structures to ensure resistance to fracture at various temperatures. In this study, a series of experiments is carried out to obtain fracture toughness values (CTOD) of API 2W Gr.50B, welded using FCAW(Flux Cored Arc Weld). In particular, a comparison of absorbed impact energy and CTOD values are made with respect to two different welding groove shapes; double-V-groove and double-bevel-groove. Charpy impact tests are performed for specimens sampled near the root gap, and CTOD tests are carried out for three point bending specimens having the notch at weld zone. While Charpy impact test result is determined to be a good qualitative measure of fracture toughness, no quantitative correspondence between impact absorbed energy and CTOD values was found. Based on the experiment, it is observed that double-V-groove welds give lower transition temperature than those of double-bevel-groove.

The study of ignition characteristics of solid propellant using Arc Image Furnace (광학특성을 이용한 고체추진제 점화특성 연구)

  • Yoo, Ji-Chang;Kim, In-Chul;Jung, Jung-Yong;Lee, Kyung-Joo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.225-228
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    • 2007
  • The objective of this study is to characterize design parameters of rocket igniters for composite, double base and nitramine propellant. Arc image furnace and fiber optics surface reflectometer were used to measure ignition delay time and reflected optical energy of several compositions of composite, double base and nitramine base rocket propellant at different pressure levels each other. The order of ignitability was double base > composite > Nitramine propellants at initial pressure of over 75 psia. The highest ignition energy was needed to ignite nitramine propellant, however, as the pressure increased up to the range of $75{\sim}400$ psia as the ignition delay time decreased abruptly. The absorbtion of radiation energy could be increased by the addition of small amount of opacifiers as carbon black, ZrC, WC and burning catalyst.

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Design and Performance Evaluation of MIMO Antenna for Handheld Devices (휴대 단말형 MIMO 안테나 설계 및 성능 평가)

  • Moon, Hyo-Sang;Jun, Kye-Suk;Lee, Bom-Son
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12A
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    • pp.1233-1241
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    • 2008
  • We design, fabricate, and measure a MIMO antenna system mountable on a small PCB (such as UMPC). The proposed antenna system accommodates three radiation elements on the PCB area of $40mm\;{\times}\;100mm$. Two of them employ a slot type and one uses a modified monopole with an inverted L shape expecting high isolation and polarization purity. The bandwidth of each proposed MIMO antenna ranges from 80MHz and 200MHz at the center frequency of 1.8 GHz. The isolations between ports have been found to be greater than 10dB over the interested frequency band. Besides, the proposed MIMO system has been evaluated in terms of ARC(Active Reflection Coefficient, TARC(Total ARC), correlation, MEG, and etc. The envelope correlation is calculated to be much less than 0.04 and the ratio of the mean effective gain(MEG) between the antennas is found to be close to unity.

GIS- Based Predictive Model for Measure of Environmental Pollutant (GIS를 이용한 환경오염의 예측 모델)

  • Lee, Ja-Won
    • Journal of the Korean association of regional geographers
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    • v.14 no.2
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    • pp.114-125
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    • 2008
  • Colored dissolved organic matter(CDOM) is an important component of ocean color that can be used as an invaluable tool in water quality and ocean color studies. With the largest source of coastal CDOM appearing to be from freshwater discharge into the ocean, coastal predictive models will do much to refine our knowledge about major processes that control CDOM distributions in coastal waters and provide a better insight into the global carbon cycle. This study aims at developing a GIS-based watershed-scale predictive model of CDOM distributions in Neponset river watersheds that can be used to appraise our understanding of CDOM sources and distributions in coastal waters and predict the response of CDOM concentration to changes in land use patterns. Weighting factors are developed for CDOM freshwater sources after extensive groundtruthing from various landuse types in the watershed. This model makes use of a publicly available DEM(Digital elevation model) as the base data for analysis. Stream networks, discharge, and land use data are used from public repositories while sub- watershed delineation, pour-points, and land use parcels are generated using Spatial Analysis of ArcGIS 9.2 to estimate the CDOM loading from various sources to the lower tributaries of rivers. The Neponset Watershed in eastern Massachusetts is selected as the site for development of the model.

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A Study of Measurement on the Head and Face for Korean Adults (한국 성인의 머리 및 얼굴부위 측정치에 관한 연구)

  • Yoon, Hoon-Yong;Jung, Suk-Gil
    • IE interfaces
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    • v.15 no.2
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    • pp.199-208
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    • 2002
  • This study was performed to measure the various dimensions of the head and face for Korean adults. Three hundred and eighteen males and two hundred and sixty females, age ranged 18 to 60, participated for this study. Thirty-six dimensions were selected to measure. Subjects were divided into three age groups - 18 to 29, 30 to 39, and 40 to 60 - for each sex. The data were analyzed ta see the differences between the age groups and sex using SAS program. Also, the results of this study were compared to the data of Japanese and US. army. The results showed that the 'ear length', 'bigonial breadth' and 'bitragion submandibular arc' increased as the age increased(p<0.01). However, not much of differences were shown between the age groups in most of other dimensions. Males were significantly bigger than females in every dimensions. The comparison between Korea and Japanese showed significant differences in many dimensions. Due to this reason, it is considered that more caution has to be exercised in using Japanese data for the Korean. The Americans showed to be significantly bigger than Korean in most dimensions. It showed that Koreans have more roundish face and wider nose ridge than Americans. The results of this study can be used to design the products that related to the head and face.

Identification of Urban Stream Sandbar Change After Concentrated Storm during Summer (집중호우 후 도시 자연형하천의 사주변화 파악)

  • Kim, Jae-Cheol;Lee, Sang-Hwa;Shin, Dong-Hoon;Lee, Kyoo-Seock
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.9 no.6
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    • pp.162-167
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    • 2006
  • The urban stream includes the channel and sandbars. The sandbar plays a key role in the riparian ecosystem. For birds and insects the sandbar offers a small strip of habitat and fish and other fauna feed in the boundary of sandbar where eddies occur. So, it is important habitat and source for the flow of energy, matter and organisms through the landscape and act as ecotone between the terrestrial and stream corridors. However, the sandbar changes continuously by the natural process. Thus, it is necessary to measure the shape and area of the sandbar accurately for the efficient urban stream management for the amenity of urban residents and stream protection. The study site is Yangjae Stream where the first natural-style urban stream restoration projected was impelemented by the support of Ministry of Education in Korea. The measurement was taken by the beacon Differential Global Positioning System (DGPS) and the data were stored and analyzed using ArcView Geographic Information System (GIS) program. Therefore, the purpose of this study is to measure the change of sandbars in the urban stream after concentrated stormwater during summer.

Explorations of Hydrothermal Vents in Southern Mariana Arc Submarine Volcanoes using ROV Hemire (심해무인잠수정 해미래를 이용한 남마리아나 아크 해저화산 열수분출공 탐사)

  • Lee, Pan-Mook;Jun, Bong-Huan;Baek, Hyuk;Kim, Banghyun;Shim, Hyungwon;Park, Jin-Yeong;Yoo, Seong-Yeol;Jeong, Woo-Young;Baek, Sehun;Kim, Woong-Seo
    • Journal of Ocean Engineering and Technology
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    • v.30 no.5
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    • pp.389-399
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    • 2016
  • This paper presents the explorations of hydrothermal vents located in the Marina Arc and Back Arc Basin using the deep-sea ROV Hemire. These explorations were conducted by KRISO and KIOST to demonstrate the capability of Hemire in various applications for deep-sea scientific research. The missions included the following: (1) to search the reported vents, (2) conduct visual inspections, (3) deploy/recover a sediment trap and bait traps, (4) sample sediment/water/rock, (5) measure the magnetic field at the vent site, and (6) acquire a detailed map using multi-beam sonar near the bottom. We installed three HD cameras for precise visual inspection, a high-temperature thermometer, a three-component magnetometer, and a multi-beam sonar to acquire details of the bottom contour or identify vents in the survey area. The explorations were performed in an expedition from March 23 to April 5, 2016, and the missions were successfully completed. This paper discusses the operational process, navigation, and control of Hemire, as well as the exploration results.

FIT OF IMPLANT FRAMEWORKS FABRICATED BY ONE-PIECE CASTING, LASER WELDING, SOLDERING, AND ELECTRIC DISCHARGE MACHINING (일체주조법, 레이저용접법, 납착법, 방전가공법에 의해 제작된 임플란트 보철물의 적합도에 관한 연구)

  • Seol, Young-Hoon;Jeong, Chang-Mo;Jeon, Young-Chan;Kang, Sung-Won
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.2
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    • pp.156-171
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    • 2002
  • The purpose of this study was to measure and compare the strains produced by screw-tightening implant frameworks fabricated by aye different fabrication methods; (1) one-piece cast using plastic sleeve, (2) one-piece cast using gold cylinder, (3) laser welding, (4) soldering, and (5) electrical discharge machining, and also to measure and compare the strains produced when the order of screw tightening was changed A research model incorporating eighteen strain gages was made to measure the fit of implant frameworks in three dimensions. Three implants aligned in an arc were fixed on the top ends of the L-shape aluminum bars of the research model, and standard abutments were joined to the implants with abutment screws. Five types of implant framework were placed on the abutments and screwed by a torque wrench using 10 Ncm. Under the conditions of this study, the following conclusions were drawn: 1. The electrical discharge machining group showed the smallest magnitude of strain, followed by the soldering group, the laser welding group, the one-piece cast group using gold cylinder, and the one-piece cast group using plastic sleeve. However, among the magnitude of strain for the remaining groups except the electrical discharge machining group, there were not significant differences. 2. When the order of screw tightening was changed, there were not significant differences in the magnitude of strain. 3. In comparison with the electrical discharge machining group, the laser welding group and the one-piece cast groups showed greater horizontal distortion and the soldering group showed greater horizontal and vertical distortion.