• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.16-23
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• 2019

This paper describes the design and analysis of a periscope imaging system installed at the engine test facility in the Agency for Defense Development. The periscope system is a cylinder-shaped image observation system installed at the rear of the engine and at the top of the diffuser. The periscope system has high risk of breaking because it is directly affected by high temperature (2300 K) and products of combustion. Thus, we used 1D heat transfer calculation, and 2D and 3D CFD analysis to confirm the heat flux and temperature distribution. Also, the cooling performance was verified. In the current design, using the periscope system, we can see flame shapes, control of the nozzle, and stability of the exhaust flow visually.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.199-206
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• 2021

This paper describes the feasibility and reliability verification of installing a protective structure to protect attack periscopes. The attack periscope is the critical equipment of a submarine to enable the user to monitor surface and air activity, collect navigational data, and detect and identify targets. The attack periscope provides target information acquired through TV, IR camera, and laser range finder to the combat system. In the product improvement program, the upper part of the masts was exposed to the outside of the sail because the existing attack periscope was replaced with a new one. On the other hand, the head sensor can be damaged by floating objects, such as fishing nets, during sea navigation. Therefore, the installation of a protective structure for an attack periscope improved the equipment operation performance. The feasibility and reliability of the installation of the protective structure were verified by examining the influence of URN.

• Journal of Information Science Theory and Practice
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• v.5 no.1
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• pp.65-84
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• 2017

Three most popular information services, Periscope, Ustream, and YouNow, vicarious for all Social Live-Streaming Services (SLSSs), are investigated to analyze their streamers' motivations and the user-generated content. Additionally, we collected demographic data (gender and age). More than 7,500 streams by users from the U.S., Germany, and Japan were observed. Main streamer motivations on SLSSs are boredom, socializing, the need to reach a specific group, the need to communicate, and fun. Important content categories on all three SLSSs are chatting, sharing information, 24/7, and 'slice of life.' We were able to identify differences between users from the U.S., Germany, and Japan as well as between the users of Periscope, Ustream, and YouNow. The main motive to stream in the U.S. is to reach a specific group, while in Japan it is socializing, and in Germany boredom. The top content category for both, YouNow as well as Periscope, is to chat; on Ustream it is 24/7 (i.e., webcams).

• Journal of the Korea Society of Computer and Information
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• v.29 no.1
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• pp.131-138
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• 2024

The ability of Combat Management System(CMS) to respond quickly and accurately to threat to a naval vessel is directly related to the survivability and combat power of the vessel. However, current method for detecting enemy submarine periscope in CMS rely on manual and subjective method that require operators to manually verify and analyze information received from sensor. This delays the response time to the threat, making the vessel less viable. This paper introduces a periscope detection algorithm that classifies the plot information generated by High Resolution Range Profile(HRRP) into probability-based suspicion classes and dramatically reduces threat response time through classified notifications. Algorithm validation showed 133.3791 × 10⁶ times faster and 12.78%p higher detection rate than operator, confirming the potential for reduces threat response time to increase vessel survivability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.8
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• pp.661-669
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• 2017

This paper describes an MMTI(Maritime Moving Target Indicator) for periscope detection in airborne radar. Firstly, we analyze the characteristics of sea clutter, sea targets. Secondly, we study the differences between GMTI(Ground Moving Target Indicator) and MMTI. This paper proposes an optimal MMTI operating environment and method. We also suggest a signal processing algorithm using STAP(Space-Time Adaptive Processing) for detecting small RCS target moving low speed. The detection probability for moving target with MDV(Minimum Detectable Velocity) is simulated under various RCS and multi-channel system. Finally, we analyze the major performance for range, velocity and azimuth accuracy.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.520-525
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• 2003

Fast Breeder Test Reactor (FBTR) is a 40MW (thermal) / 13.2MW (electrical), Plutonium - Uranium mixed carbide fuelled, sodium cooled, loop type nuclear reactor operating at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. Its main aim is to generate experience in operation of fast reactors and sodium systems and to serve as an irradiation facility for development of fuels and structural materials fur fast reactors. Nuclear reactors pose difficulties to the NDT techniques used to monitor the conditions of the internal components. Sodium cooled fast breeder reactors have their own typical difficulties in using the NDT techniques. These are due to the need for operation in aggressive environment of nuclear radiation and sodium (molten/vapour), as well as the need to maintain leak tightness of a very high order during all states of reactor operation and shutdown for fuel handling, maintenance and remote inspection. This paper discusses the following NDT techniques, which have been successfully used for the past 15 years in FBTR: (i) Periscope and Projector, (ii) Core Co-ordinate Measuring Device and, (iii) Optical fiberscope. The inspection using these techniques have given confidence for further reactor operation at high power by giving useful data on the conditions of the components inside the reactor vessel.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1330-1334
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• 2012

The submarines reach their weakest point when they sail on the surface to operate snorkel and periscope. At this period, however, there lies a high possibility that the submarines are detected by non-acoustic sensors such as radars, IR signatures, and human observations. In this paper, the non-acoustic stealth was adopted on the mast and periscope of submarines so as to overcome their vulnerability of being easily detected in this given situation. First of all, the non-acoustic detection sensors were investigated and the stealth methods were analyzed. And multi-layered structures consisting of RAM layer, IR layer, and Camouflage layer were proposed on the surface of the submarine. As a results, multi-layered structure was suggested with 3~5 mm of a magnetic material such as ferrite for RAM layer, 1~2 mm of ceramic or nickel for IR layer, and sea-blue paint for Camouflage layer.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.133-138
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• 2010

This paper describes on aerodynamic characteristics of pantograph system for Next generation high speed train(HEMU-400). The pantograph which supports electric power is located on the roof. Because of this, it generate high drag, severe acoustic noise and vibration which induced unstable flow due to complex configuration. Therefore, the design of high efficient pantograph needs to increase operational speed. In this research, wind tunnel tests were performed to design a high efficient pantograph system using 1/4 scaled model which were KTX-II pantograph, single arm pantograph and periscope type pantograph with square cylinder shape panhead and optimized shape panhead. For real operational condition, flow directions were adapted by rotation of pantograph. From this results of wind tunnel, it is checked that the pantograph with optimized panhead and single arm type or periscope type has better aerodynamic performance. In addition, lift control device and spoiler in pantograph were tested to investigate the validity of application.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.6 s.150
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• pp.647-655
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• 2006

In this paper, submerged body dynamics model in vertical plane which can include the effect of free surface and wave is suggested to simulate the motions of submerged body moving beneath free surface precisely. A controller is designed, which can maintain a constant depth below the mean sea level and minimize the pitch angle. Numerical simulations show that the designed controller is effective on depth keeping and minimizing pitch angle in regular waves and irregular waves.

• Journal of Information Technology Applications and Management
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• v.27 no.6
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• pp.31-51
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• 2020

During the last decade, social live streaming service like Periscope, Ustream, and YouNow has developed from a niche market into a mainstream activity. In this media environment, social live streaming service has a tremendous impact on the social behaviors of users. Despite the rapid development, there are a lack of studies to make better understand the media environment changes through social live streaming service. This study adopted an affordances approach that leads us to identify six distinctive social affordances (visibility, accessibility, information sharing, social interaction, role-taking, interactive revenue) for user engagement in social live streaming service. Specifically, this study explores the impact of social affordances on perceived flow, followed by user engagement including passive and active engagement. Empirical data analysis with 258 questionnaires suggests that social affordances affected users' flow perception, and flow has an effect on active as well as passive engagement. Contrary to the expectation in a hypothesized research model, only the impact of accessibility on flow was rejected.