• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.59-64
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• 2019

Recently, time synchronous has become important for satellite launch control facilities, multiple thermal power plants, and power system facilities. Information from time synchronous at each of these industrial sites requires time synchronization to control or monitor the system with correlation. In this paper, IRIG-B codes, which can be used for time synchronous, are used as specifications in IRIG standard 200-16. Signals from IRIG-B120 (Analog), IRIG-B000 (Digital), and one PPS are output from GPS receiver. Using the signal from IRIG-B120 (Analog), it passes through the signal from the analog amplifier and generates one PPS signal using the field-programmable gate array. The FPGA is used cyclone EPM570T100I5N. According to IEEE regulations, the error of one PPS is specified within 1us, but in this paper, the error is within 100ns. The output of the one PPS signal was then compared and tested against the one PPS signal on the GPS receiver to verify accuracy and reliability. In addition, the proposed time synchronous is simple to construct and structure, easy to implement, and provides high time precision compared to typical time synchronous. The output of the one PPS signals and IRIG-B000 signal will be used in many industry sectors.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.74-82
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• 2004

In digital broadcasting, applications are computer programs executed by the set-top box(TV receiver) , and synchronized applications are those that perform tasks at the specified moments in the underlying video. This paper describes important concepts, standards, and skills needed to implement synchronized applications and explains how to integrate them to implement these applications. This Paper assumes the European data broadcasting standard, DVB-MHP. In DVB-MHP, scheduled stream events are recommended as a means of synchronizing applications with video streams. In this method, the application receives each stream event, and executes the action associated with the stream event at the time specified in the stream event. Commercially available stream generators, i.e., multiplexers, do not generate transport streams that support scheduled stream events. So we used a stream generator implemented in our lab. We implemented a synchronized application where the actions triggered by stream events are to display graphic images. We found that our synchronized application processes scheduled stream events successfully. In our experimentation, the stream events were synchronized with the video and the deviation from the intended time was within 240 ㎳, which is a tolerance for synchronization skew between graphic images and video.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1113-1122
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• 1999

In this paper, we propose MSS(Multicast Synchronization Server) and QCS(QoS Conversion Server) models that can support IP multicast and QoS(Quality of Service) over the ATM network more efficiently. In the MSS model, it is possible to establish shortcut VCs(Virtual Circuits) among all hosts in the ATM network and to transfer multicast data at high speed. Also the MSS model is more scalable, because the number of inter-cluster VCs needed in the MSS model is less than that of EARTH. In the QCS model, ATM switch is modified to support one QoS service and best effort service through the one point-to-multipoint VC at the same time so required network resources are reduced, and dedicated server is used for QoS conversion to accept heterogeneous receivers more efficiently. In this Paper, the proposed MSS model and QCS model have solved both efficiency problem and scalability problem. It is proved through the comparison of the VCs required in each model.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.183-189
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• 2020

The pregnancy rate in indigenous ewes inseminated with frozen-thawed Suffolk semen following natural and synchronized estrus was determined. The serum Progesterone and Estrogen concentration and vaginal electrical resistance (VER) of ewes at the time of Artificial Insemination (AI) were observed as successful pregnancy determinants. 21 healthy ewes were selected for this experiment during January-April, 2017. 10 ewes were inseminated in natural estrus. Whereas, 11 ewes were inseminated after estrus synchronization using intravaginal sponges containing 60 mg medroxyprogesterone acetate. Trans-cervical Al (TCAI) was performed in all ewes within 12-16 hours of observed heat. Prostaglandin E₁ analogue impregnated vaginal sponge was used for cervical relaxation 6-8 hours before insemination. Pregnancy was diagnosed through trans-abdominal ultrasonography after 40 days of AI. The pregnancy rate of ewes in synchronized estrus was higher (54.5%) than in natural estrus (30%). Higher serum Progesterone level (0.90 ± 0.02 ng/mL) and significantly (p < 0.001) lower VER (257.78 ± 10.11 ohm) were observed at the time of AI in ewes becoming pregnant. Results suggest that higher Progesterone concentration and lower VER could be considered as pregnancy indicators. Oestrous synchronization could be implemented to increase the pregnancy rate in ewes.

• Journal of the Korea Society of Computer and Information
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• v.18 no.7
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• pp.47-55
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• 2013

Most of the applications implemented in embedded systems use timers equipped in MCU. The purposes of timer usage of the applications lie in a wide range of areas such as implementing software timers of real-time operating systems to measuring processing time of sensors. The elapsed times measured by the applications are various in length as well as in precision ranging from several us to several hundreds of ms. The paper analyzes the timing error factors caused by un- synchronizing timer clock pulse when timers are manipulated, and proposes a method of how to synchronize timer clock pulse to reduce the timing errors. As a result of an experiment, this paper shows that an error of 230us is reduced within 10us in case of appling the proposed method to a 4096Hz timer prescaled from 32768Hz by 8.

• Journal of Korea Multimedia Society
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• v.3 no.6
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• pp.611-616
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• 2000

By the most important media to deliver the contents on a remote instruction we commonly use audio and documents. A number of remote instruction system are trying to offer the video, but they did not acquire satisfiable results because of the limited network and width. Also, they use the general web browsers that have a lot of unspecific users access the contents. Also, they use the general web browsers that have a lot of unspecific users access the contents. Like this most systems that use the continuous media have not offer the satisfiable contents because of the network limitation. Moreover, because they use the web browser, they offer the contents having documents(web pages) only. In this paper, we propose a web-based remote instruction system on real-time using audio and documents which are the most important media for a information delivery. In addition to the system, we use a action synchronization mechanism between the web browsers. If the instructor uses web pages on his computer and explains the contents of them, the learners see the same web pages as the instructor's and listens to his voice.

• Journal of Advanced Navigation Technology
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• v.11 no.2
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• pp.163-169
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• 2007

In this paper, we propose a method of trigger pulse generation to capture the image on time by making a synchronization between the x-ray generator and digital x-ray image acquisition system. we designed a wireless trigger pulse generation circuit to make a synchronization between x-ray generator and digital image acquisition system and analysis its performance. When it starts to detect a certain level of x-ray radiation or above from the air, this method starts to generate a ACQ_START signal to indicate the timing for image acquisition starting from digital image acquisition system. Hence, when it starts to detect under certain level of x-ray signal from the air, this method starts to generate a ACC_END signal to indicate the timing for image acquisition stop from digital image acquisition system. Image acquisition is activated only this time between ACQ_START and ACQ_END signal. By doing this wireless detecting of x-ray signal from remote, we can get more accurate timing for capturing the x-ray image and any type of x-ray generator can be connected to digital image acquisition system, regards of wired protocol. This makes easy installation. We could get 3.5 line pair / mm resolution at 20 mAs of x-ray level with resolution chart. This is same or better image comparing to conventional wired result.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.1-13
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• 2007

GPS/GIS and RFID technologies have been changing the paradigm af our society toward ubiquitous era. Especially, geographically distributed mobile agents with transporting objects need to be automatically recognizable and traceable under certain conditions. To do this, fundamental theories and technologies are required to specify and verify spatial and temporal behaviors of agents on geographical space. This paper presents a new formal method, called Calculus of Real-Time Distribution, Mobility, and Interaction (CaRDMI), for this purpose. For specification, CaRDMI defines a map, mobile agents with transporting objects. The movement of on agent is represented by a path on the map, consisting of a list of nodes and a list of edges with spatial and temporal constraints. Interactive constraints among agents are represented by synchronization modes on objects at nodes. These constraints are distinguishable features of CaRDMI from other methods. Especially, many-to-many timed synchronization constraints are noticeable. For verification, CaRDMI presents the spatial, temporal and interactive deduction rules and the spatial and temporal equivalence relations.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.48-55
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• 2012

The number of digital content used in mobile devices such as smartphones or tablet PCs has been rapidly increasing along with the development of IT industry. At the same time, studies on digital content management are actively conducted. One of the previous studies defined CTI(Content Tracking Information) for efficient management of the information on digital content usage between mobile devices in an area in which the internet is inaccessible, and suggested ways to deal with CTI management, reduction of the overhead and a technique of collecting as many CTIs as possible within a short time. This paper presents the design and implementation of a simulator capable of verifying the logic and the performance of the CTI management method. This tool simulates a mobile environment where devices move around in the internet inaccessible area and propagates digital contents each other. It shows several advantages including the efficient synchronization of CTI management and overhead reduction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.977-985
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• 2012

Recently, many countries have been developing new protocols to improve the performance of tactical ad hoc networks for implementing NCW (Network Centric Warfare). Combat net radio (CNR) networks are the most important communication infra for the ground forces such as infantry of Army. U.S. Army had developed MIL-STD-188-220D that is the Interoperability Standard for DMTDs (Digital Messages Transfer Device Subsystems) for voice and data communication in CNR. MIL-STD-188-220D is a candidate for MAC protocol of TMMR which is next radio and has a few constraints to used in TMMR. NAD (Network Access Delay) defined in MIL-STD-188-220D needs time synchronization to avoid collision. However, it is difficult for time synchronization to fit in multi-hop environment. We suggest the enhanced DAP (Deterministic Adaptable Priority)-NAD to prevent conflicts and decrease delays in multi-hop CNR. Simulation results show that the proposed scheme improves the performance in multi-hop CNR networks.