• Title/Summary/Keyword: Time Delays

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Computation of Maintainability Index Using SysML-Based M&S Technique for Improved Weapon Systems Development (SysML 기반 모델링 및 시뮬레이션 기법을 활용한 무기체계 정비도 지수 산출)

  • Yoo, Yeon-Yong;Lee, Jae-Chon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.88-95
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    • 2018
  • Maintainability indicates how easily a system can be restored to the normal state when a system failure occurs. Systems developed to have high maintainability can be competitive due to reduced maintenance time, workforce and resources. Quantification of the maintainability is possible in many ways, but only after prototype production or with historical data. As such, the graph theory and 3D model data have been used, but there are limitations in management efficiency and early use. To solve this problem, we studied the maintainability index of weapon systems using SysML-based modeling and simulation technique. A SysML structure diagram was generated to simultaneously model the system design and maintainability of system components by reflecting the maintainability attributes acquired from the system engineering tool. Then, a SysML parametric diagram was created to quantify the maintainability through simulation linked with MATLAB. As a result, an integrated model to account for system design and maintainability simultaneously has been presented. The model can be used from early design stages to identify components with low maintainability index. The design of such components can be changed to improve maintainability and thus to reduce the risks of cost overruns and time delays due to belated design changes.

Flood Disaster Prediction and Prevention through Hybrid BigData Analysis (하이브리드 빅데이터 분석을 통한 홍수 재해 예측 및 예방)

  • Ki-Yeol Eom;Jai-Hyun Lee
    • The Journal of Bigdata
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    • v.8 no.1
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    • pp.99-109
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    • 2023
  • Recently, not only in Korea but also around the world, we have been experiencing constant disasters such as typhoons, wildfires, and heavy rains. The property damage caused by typhoons and heavy rain in South Korea alone has exceeded 1 trillion won. These disasters have resulted in significant loss of life and property damage, and the recovery process will also take a considerable amount of time. In addition, the government's contingency funds are insufficient for the current situation. To prevent and effectively respond to these issues, it is necessary to collect and analyze accurate data in real-time. However, delays and data loss can occur depending on the environment where the sensors are located, the status of the communication network, and the receiving servers. In this paper, we propose a two-stage hybrid situation analysis and prediction algorithm that can accurately analyze even in such communication network conditions. In the first step, data on river and stream levels are collected, filtered, and refined from diverse sensors of different types and stored in a bigdata. An AI rule-based inference algorithm is applied to analyze the crisis alert levels. If the rainfall exceeds a certain threshold, but it remains below the desired level of interest, the second step of deep learning image analysis is performed to determine the final crisis alert level.

A Study on the Indicators of Language Development Ability in Infants 18-24 Months (영아(18-24개월)의 언어발달능력 지표에 관한 조사 연구)

  • Kyung-sook Hwang;Wha-Soo Kim;Ji-Woo Lee
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.843-848
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    • 2023
  • The purpose of this study is to understand in detail the development of infants in the 18-24-month period when language develops the most, and to prepare new standards for developmental evaluation that can promote appropriate intervention design at an early time. We divided sub-items such as screening tests and standardized test tools to know the language development ability indicators of infants aged 18-24 months were divided into syntax/phonology, meaning, and speech, and each question was classified and a checklist was made on a five-point scale to conduct a survey on parents with infants aged 18-24 months. Low sensitivity to screening of infants with language delays in nationally implemented infant health checkups, and domestic test tools are standardized for at least six to as many as 10 years, which is always possible in questionnaires related to acceptance and expression, with many reports from parents or teachers.The proportion of "wow" and "started to do" was more than 50-60%. Based on the results of this study, it is hoped that new standards for developmental evaluation will be developed to promote the design of appropriate interventions in detail at a short time.

A Study on Operating Vertiport Cooperative Decision Making (버티포트 협력적 의사결정지원체계 운용방안연구)

  • Jae-wook Chun;Ye-seung Hwang;Gang-san Kim;Eui Jang;Yeong-min Sim;Woo-choon Moon
    • Journal of Advanced Navigation Technology
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    • v.27 no.6
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    • pp.690-698
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    • 2023
  • Information sharing and decision making between airport stakeholders became possible after the introduction of airport cooperative making system (A-CDM). This also resulted in optimizing aircraft handling time and increased the efficiency of aircraft operations. Technological advances have recently led to the development of urban air mobility (UAM) which is a small aircraft taking off and landing vertically. It is emerging as a new air transportation system in the future due to its advantage of saving time and solving congestion problem in the urban area. This study aims to suggest how vertiport cooperative decision making system (V-CDM) should be managed for efficient operation of UAM. By establishing procedure for decision making system based on Vertiport ecosystem of UAM. By establishing procedure for decision making system based on Vertiport ecosystem and UAM aircraft, unnecessary flight delays or cancellations can be minimized and efficiency of UAM operation will be improved as well.

Use of custom glenoid components for reverse total shoulder arthroplasty

  • Punyawat Apiwatanakul;Prashant Meshram;Andrew B. Harris;Joel Bervell;Piotr Lukasiewicz;Ridge Maxson;Matthew J. Best;Edward G. McFarland
    • Clinics in Shoulder and Elbow
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    • v.26 no.4
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    • pp.343-350
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    • 2023
  • Background: Our purpose was to evaluate a custom reverse total shoulder arthroplasty glenoid baseplate for severe glenoid deficiency, emphasizing the challenges with this approach, including short-term clinical and radiographic outcomes and complications. Methods: This was a single-institution, retrospective series of 29 patients between January 2017 and December 2022 for whom a custom glenoid component was created for extensive glenoid bone loss. Patients were evaluated preoperatively and at intervals for up to 5 years. All received preoperative physical examinations, plain radiographs, and computed tomography (CT). Intra- and postoperative complications are reported. Results: Of 29 patients, delays resulted in only undergoing surgery, and in three of those, the implant did not match the glenoid. For those three, the time from CT scan to implantation averaged 7.6 months (range, 6.1-10.7 months), compared with 5.5 months (range, 2-8.6 months) for those whose implants fit. In patients with at least 2-year follow-up (n=9), no failures occurred. Significant improvements were observed in all patient-reported outcome measures in those nine patients (American Shoulder and Elbow Score, P<0.01; Simple Shoulder Test, P=0.02; Single Assessment Numeric Evaluation, P<0.01; Western Ontario Osteoarthritis of the Shoulder Index, P<0.01). Range of motion improved for forward flexion and abduction (P=0.03 for both) and internal rotation up the back (P=0.02). Pain and satisfaction also improved (P<0.01 for both). Conclusions: Prolonged time (>6 months) from CT scan to device implantation resulted in bone loss that rendered the implants unusable. Satisfactory short-term radiographic and clinical follow-up can be achieved with a well-fitting device. Level of evidence: III.

Investigation and Processing of Seismic Reflection Data Collected from a Water-Land Area Using a Land Nodal Airgun System (수륙 경계지역에서 얻어진 육상 노달 에어건 탄성파탐사 자료의 고찰 및 자료처리)

  • Lee, Donghoon;Jang, Seonghyung;Kang, Nyeonkeon;Kim, Hyun-do;Kim, Kwansoo;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.603-620
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    • 2021
  • A land nodal seismic system was employed to acquire seismic reflection data using stand-alone cable-free receivers in a land-river area. Acquiring reliable data using this technology is very cost effective, as it avoids topographic problems in the deployment and collection of receivers. The land nodal airgun system deployed on the mouth of the Hyungsan River (in Pohang, Gyeongsangbuk Province) used airgun sources in the river and receivers on the riverbank, with subparallel source and receiver lines, approximately 120 m-spaced. Seismic data collected on the riverbank are characterized by a low signal-to-noise (S/N) and inconsistent reflection events. Most of the events are represented by hyperbola in the field records, including direct waves, guided waves, air waves, and Scholte surface waves, in contrast to the straight lines in the data collected conventionally where source and receiver lines are coincident. The processing strategy included enhancing the signal behind the low-frequency large-amplitude noise with a cascaded application of bandpass and f-k filters for the attenuation of air waves. Static time delays caused by the cross-offset distance between sources and receivers are corrected, with a focus on mapping the shallow reflections obscured by guided wave and air wave noise. A new time-distance equation and curve for direct and air waves are suggested for the correction of the static time delay caused by the cross-offset between source and receiver. Investigation of the minimum cross-offset gathers shows well-aligned shallow reflections around 200 ms after time-shift correction. This time-delay static correction based on the direct wave is found essential to improving the data from parallel source and receiver lines. Data acquisition and processing strategies developed in this study for land nodal airgun seismic systems will be readily applicable to seismic data from land-sea areas when high-resolution signal data becomes available in the future for investigation of shallow gas reservoirs, faults, and engineering designs for the development of coastal areas.

Smart Browser based on Semantic Web using RFID Technology (RFID 기술을 이용한 시맨틱 웹 기반 스마트 브라우저)

  • Song, Chang-Woo;Lee, Jung-Hyun
    • The Journal of the Korea Contents Association
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    • v.8 no.12
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    • pp.37-44
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    • 2008
  • Data entered into RFID tags are used for saving costs and enhancing competitiveness in the development of applications in various industrial areas. RFID readers perform the identification and search of hundreds of objects, which are tags. RFID technology that identifies objects on request of dynamic linking and tracking is composed of application components supporting information infrastructure. Despite their many advantages, existing applications, which do not consider elements related to real.time data communication among remote RFID devices, cannot support connections among heterogeneous devices effectively. As different network devices are installed in applications separately and go through different query analysis processes, there happen the delays of monitoring or errors in data conversion. The present study implements a RFID database handling system in semantic Web environment for integrated management of information extracted from RFID tags regardless of application. Users’ RFID tags are identified by a RFID reader mounted on an application, and the data are sent to the RFID database processing system, and then the process converts the information into a semantic Web language. Data transmitted on the standardized semantic Web base are translated by a smart browser and displayed on the screen. The use of a semantic Web language enables reasoning on meaningful relations and this, in turn, makes it easy to expand the functions by adding modules.

Profiling Approach for the Choice between Speculation and Postponement Strategy in Supply Chain Management (공급사슬관리의 예측전략과 지연전략 선택을 위한 프로파일링 접근법)

  • Kang, Sung-Wook;Kim, Gyu-Bae
    • Journal of Distribution Science
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    • v.12 no.4
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    • pp.47-54
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    • 2014
  • Purpose - The postponement strategy, which delays the form, place, and production of products as late as possible, has been widely considered as a competitive supply chain management scheme in an era of mass customization and modular manufacturing. An interesting business phenomenon is that not all manufacturing/logistics firms choose the postponement strategy. Given that postponement is a counter-measure to speculation, which has some advantages under certain environments, the current imprudent inclination toward the postponement strategy may cause firms to lose the potential of the speculation strategy, an alternative strategy in supply chain management. Building on the logistics and manufacturing literature, this study examines characteristics of two contrasting strategies, postponement and speculation, and major factors favoring each strategy. Research design, data, and methodology - We apply the profiling approach to two business cases, HP printer and LG mobile phone. The profiling approach is a method of choosing a particular strategy aligned with environmental factors. While various approaches have been used to check the fit between a business strategy and environmental factors, the literature on manufacturing strategy and logistics has commonly adopted the profiling approach. Major factors used in profiling variables are derived from the literature. Two samples, HP printer and LG mobile phone, are selected, because they represent major characteristics appropriate for each strategy. The profiling is based on data from semi-organized interviews with managers. Results - The profiling approach shows that the postponement strategy is a suitable one for HP printers. Most factors, such as product life cycle, large production volume, low-price, product value, and monetary density, support delaying end products until as late as possible. Despite some exceptions, such as delivery time and economy of scale, our analysis states that the overall profile of HP printer is favorable for the postponement strategy. On the other hand, LG mobile phone may adapt the speculation strategy. Although it has large production volume and low delivery frequency, most characteristics support the speculation strategy for this product. An interesting finding is that, despite common perception that advanced technology products such as mobile telephones favor the postponement strategy, profiling proposes the speculation strategy for this product. Conclusions - Our analysis shows that speculation is not the universal option for supply chain management, and that, when choosing a specific strategy, one should consider many factors simultaneously. A major implication of our work is to emphasize the role of environmental factors such as supply chain variables in choosing an inventory strategy, and the importance of fit rather than solely strategic orientation. A theoretical contribution is to demonstrate the benefit of the simultaneous consideration of business variables in choosing specific strategies. For practitioners, our work leads us to consider the existence and the potential of speculation as a counter-measure to postponement. In addition, the comprehensive framework in this research may be instantly used in examining a practical strategy.

Patent Analysis on 5G Technology Trends from the Perspective of Smart Factory (특허 분석을 통한 스마트공장 관점의 5G 기술개발 동향 연구)

  • Cho, Eunnuri;Chang, Tai-Woo
    • The Journal of Society for e-Business Studies
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    • v.25 no.3
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    • pp.95-108
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    • 2020
  • The development of 5G technology, which is a next-generation communication technology capable of processing large amounts of data in real-time and solving delays, is drawing attention. Not only in the United States but also Korea, 5G is focused on supporting R&D as a national strategic technology. The strategy for the smart factory, one of the core services of the 5G, aims to increase the flexibility of manufacturing production lines. The existing wired communications devices can be replaced into wireless ones with the ultra-low-delay and ultra-high-speed characteristics of 5G. For the efficient development of 5G technology, it is necessary to keep abreast of the status and trend. In this study, based on the collected data of 1517 Korea patents and 1928 US patents, 5G technologies trend was analyzed and key technologies were identified by network analysis and topic modeling. We expect that it will be used for decision making for policy establishment and technology strategy of related industries to provide the trends of technology development related to the introduction of 5G technology to smart factories.

Durability Characteristics of Concrete Containing Lightly Burnt MgO Powder (저온 소성한 MgO 분말을 혼입한 콘크리트의 내구 특성)

  • Choi, Seul-Woo;Kim, Joo-Hyung;Lee, Kwang-Myong;Kwon, Yong-Gil;Jang, Bong-Seok
    • Journal of the Korea Concrete Institute
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    • v.23 no.5
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    • pp.609-615
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    • 2011
  • MgO concrete containing lightly burnt MgO powder at $850{\sim}1,000^{\circ}C$ may have a long-term expansibility characteristic. Such expansibility of MgO concrete can compensate the shrinkage at later ages since the hydration of the MgO is very slow. However, the addition of MgO delays the initial hydration of cement and increases the setting time of cement. Also, the porosity and pore-size distribution of the MgO concrete are different from OPC concrete. Therefore, in order to use MgO in practice, both mechanical and durability properties of MgO concrete should be carefully examined. In this study, durability tests on carbonation, freezing-thawing, and diffusion of chloride were carried out after 56 days of underwater curing at $20^{\circ}C$ to compare durability characteristics of 5% MgO-mixed concrete with those of OPC concrete. The results showed that MgO concrete shows a greater durability than the concrete with no MgO, because the micro structure in the MgO concrete is much denser due to its expansibility characteristic.