• The Journal of Society for e-Business Studies
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• v.4 no.1
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• pp.87-101
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• 1999

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the control devices located in common manufacturing zone and operated by connecting them. In this paper, functional standard of the network layers are set as physical and data link layer of IEEE 802.2, 802.4, and VMD application layer and ISO-CIM reference model. Then, they are divided as minimized architecture, designed as group objects which perform group management and service objects which organizes and operates the group. For the stability in this network, this paper measures the variation of data packet length and node number and analyzes the variated value of the waiting time for the network operation. For the method of the analysis, non-exhausted service method are selected, and the arrival rates of the each data packet to the nodes that are assumed to form a Poission distribution. Then, queue model is set as M/G/1, and the analysis equation for waiting time is found. For the evalution of the performance, the length of the data packet varies from 10 bytes to 100 bytes in the operation of the group management network, the variation of the wating time is less than 10 msec. Since the waiting time in this case is less than 10 msec, response time is fast enough. Furthermore, to evaluate the real time processing of the group management network, it shows if the number of nodes is less than 40, and the average arrival time is less than 40 packet/sec, it can perform stable operation even taking the overhead such as software delay time, indicated packet service, and transmissin safety margin.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.58
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• pp.127-148
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• 2013

The Rotterdam Rules provide that port terminal operator may avoid or limit their liability for cargo loss, damage or delay in delivery or breach of any other obligation under the Rules by invoking the provisions that may provide a defence for, or limit the liability of, the carrier. Consequently the port terminal operator who are involved in the provision of maritime services may avoid or limit their liability for cargo loss, damage or delay in delivery or breach of any other obligation under the Rules. The port terminal operator to be applied for the Himalaya clause under the Rules must show that it has the requisite link with a Contracting State. In addition, the port terminal operator performs service to the period of time between the arrival of the goods at the port of loading and their departure from the port of discharge. The port terminal operator's liability for breaches of its obligation is limited to 875 SDR per package or other shipping units, or 3 SDR per kilogram of the gross weight of the goods. In addition, compensation for delay shall be limited to an amount equivalent to two and one-half times the fright payable on the goods delayed.

• The Journal of the Korea Contents Association
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• v.12 no.4
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• pp.69-75
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• 2012

In this paper, to provide various services of QoS, and moreover applying traffic ratio to CAC(Call Admission Control) algorithm tested how long average data rate and the average packet delay time. When CAC algorithm is not applied, traffic mixture ratio is 1:1:4:4, the FTP Service 0.4, web services 0.6, streaming service 0.7, the packet delay requirements are not satisfied. On the other hand CAC Algorithm is applied, all the service of packet delay are satisfied with arrival rate. Therefore, we can make sure that applying of CAC of traffic control WWW, FTP, Video, VoIP can guarantee the various services of QoS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1206-1218
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• 1992

Token ring systems which control to switch the data stream of networks by passing the token have been widely used to medium access controls in many ring or bus topology LANs. The system could be modeled for analysis as single-server-multi-queue system of the cyclic service method. These concepts could be expanded to multi-token ring systems interconnected with single ring consisting of bridges implemented simply to be stored and transmitted. In the proposal for the performance analysis of the interconnected token ring system, in has been assumed M/G/1 queueing model that frame arrivals are the Poisson process at each station queue and frame sizes are independently and identically distributed. And the average time delays were analyzed mathematically for arbitrary frame transferred from source station to destination area. The time delay of the frame transmission could be explained as the sum of the average time which the token passed from arbitrary position to source station, such as the waiting time in the source station transferring the previous arrival frames, and the propagation time from source station to interdestinated point. These delays were given as the sum of the duration from inner and outer bridge queues, the time delays from inner and outer bridge queues, and the time from outer bridge queue to destination station. These results were investigated by varing parameters effected to total time delays. In the results, those factors to be effected to dominant the total time delays were increased were in the cases of the high arrival rates and the high ration of destination of the other outerring. The system were shown the time delays increased exponentially in spite of the priority service policy. In order to decreasing the number of outerrings and increasing the number of nodes in backbone relatively, so the systems could be decreased the total delay in the interconnected token ring system.

• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.370-375
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• 2004

This paper proposes an algorithm that estimates three dimensional array shape calibration about the bottom-mounted sensor array. under the assumption that the active sources are in the far-field with unknown positions. Under some assumptions. we calculate the sensor positions via an algebraic solutions of a least squares problem that the linear equations are related to the sensor positions and directions or arrival. We give examples of algorithm performance from both computer simulations and sea test. We also illustrate the performance of sensor positions estimation as a function of time delay estimation variance and the distribution of the localizing sources.

• The Journal of Engineering Geology
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• v.13 no.1
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• pp.129-137
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• 2003

We interpreted the seismic signal characteristics from crosswell seismic tomography in the underground cavity like abandoned mines. The first arrival time delay and amplitude attenuation showed clearly at the low velocity zone of cavity and fracture. Also ray density decreased by detour of raypath. As a result of the amplitude spectrum analysis of fresh rock and low velocity zone, there were no noticeable differences of the amplitude up to about 1000Hz frequency, but indicated that the one passed around cavity decreased about 7dB at 2000Hz, and 20dB at 3000Hz. It was possible to compare the signal characteristics between two media by extracting the signal data from the fresh rock zone and the underground cavity through the seismic crosswell tomography.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.31-38
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• 1995

In this paper, we consider the leaky bucket parameter dimensioning problem in the presence of the cell delay variation(CDV) which arises at the customer premises network dud to the multiplexing with other traffic streams. We consider an ATM multiplexer in which a single CBR stream and several heterogeneous VBR traffic streams are multiplexed. Choosing an MMPP model for the bursty traffic streams, we derive an (MMPP+DD)/D/1/K queueing model for the evaluation of the CDV experienced by the CBR stream. We first evaluate the equilibrium queue length distribution embedded at tagged-cell arrival-time instants, based on whcih we calcuate the inter-cell time distribution and the distribution kof the number of tagged-cell departures in an arbitrary interval. Then we apply the analysis to the dimensionging problem of the leaky bucket parameters, examining how the employed traffic model affects the determination of the bucket size. Through numerical examples, we confirm that the Poisson traffic model can underestimate the bucket size, thus causing a considerable blocking probability for compliant use cells while the MMPP model can optimally design the bucket size which keeps the blocking probability under the target value.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.707-712
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• 2013

In patients with acute myocardial infarction (AMI), the delay from symptom onset to hospital arrival has a critical effect on morbidity and mortality. This study examined to find out the determinants of the prehospital delay in patients with AMI. The study sample consisted of 597 patients hospitalized with AMI between Jan and Dec 2009. Demographic, medical history, and clinical data were abstracted from the hospital medical records of patients with confirmed AMI, the prehospital delay was categorized as less than or greater than 6 hours. Older age, low socioeconomic status(medical aid), and low use of Emergency medical system were associated with delays in seeking emergency care for Acute myocardial infarction. Education programs to improve patient knowledge of acute coronary syndrome symptoms and promote patient responsiveness with regard to seeking medical care should be used to reduce the prehospital delay time, especially in the low socioeconomic group.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1098-1105
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• 2009

In this paper, we propose an asynchronous UWB (Ultra Wide Band) Positioning scheme that can provide precise positioning performance with low complexity and low power consumption. We also present the residual test to improve the positioning performance in multipath channels having heavy NLoS (Non-Line of Sight) components. As compared to conventional ToA (Time of Arrival) positioning scheme that requires round-trip transmissions as many as the number of beacons, the proposed UWB positioning scheme effectively decrease power consumption and processing delay since a single round-trip transmission is only required. Also, as compared to conventional TDoA (Time Difference of Arrival) positioning scheme requiring precise synchronization among the beacons, asynchronous nature of the proposed scheme achieves very low system complexity. Through simulations in LoS (Line of Sight) channel models, we observe that the proposed scheme requires low system complexity, low power consumption, while providing positioning performance of almost the same accuracy as the conventional ToA and TDoA positioning schemes. In addition, the proposed scheme by employing the residual test achieves accurate positioning performance even in multipath channels having heavy NLoS components.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.820-831
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• 1999

In this paper, we have compared the performance of a D-TDMA protocol with that of a CDMA protocol, in radio access system for integrated voice/data services.The D-TDMA protocol is based on a generic dynamic channel assignment approach to be followed a combination of “circuit mode” reservation for voice calls, along with dynamic first-come-first served assignment of remaining capacity for data messages. In the CDMA protocol, we have used the voice activity detection to reduce the interface power of other mobiles in internal and external cells, and analyzed the interference power ratio. Also we have computed BER(Bit Error Rate) by using this interference power ratio and evaluated voice blocking probability(voice packet loss probability) and data transmission delay, according to average data length and average data arrival rate.We have found the CDMA protocol achieves comparatively higher performance for short data length, regardless of data arrival rate. Otherwise, the data transmission delay of D-TDMA protocol is shorter than that of the CDMA protocol for long data message.