• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.51-54
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• 2008

In this paper, we propose a practical method for displaying 2D/True3D mixed contents in real-time. Many companies released their 3D display recently, but the costs of producing True3D contents are still very expensive. Since there are already a lot of 2D contents in the world and it is more effective to mix True3D objects into the 2D contents than making True3D contents directly, people became interested in mixing 2D/True3D contents. Moreover, real-time 2D/True3D mixing is helpful for 3D displays because the scenario of the contents can be easily changed on playback-time by adjusting the 3D effects and the motion of the True3D object interactively. In our system, True3D objects are rendered into multiple view-point images, which are composed with 2D contents by using depth information, and then they are multiplexed with pre-generated view masks. All the processes are performed on a graphics processor. We were still able to play a 2D/True3D mixed contents with Full HD resolution in real-time using a normal graphics processor.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.139-142
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• 2008

Developing from stereoscopic to autostereoscopic, researchers on display technology are trying to provide more depth cues to viewer, leading to the advent of true 3D display. Volumetric 3D displays seem to be practical technology at present. Ultimate display will function like human vision system, with characteristics of providing all depth cues and free interaction.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1371-1374
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• 2009

According to depth cues of an image, the optical engine of the solid volumetric true 3D display can project a sequence of slices of a 2D image to corresponding display at a set of liquid shutters (LC) locating at different depth. A single DLP optical engine developed for a solid volumetric true 3D display consists of a lamp, reflector, color wheel, hollow integrator, relays, DMD, and projection lens. The simulation results show that the optical engine designed for single DLP volumetric true 3D display satisfies the requirements.

• Spatial Information Research
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• v.19 no.3
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• pp.33-42
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• 2011

Since the method of generating 3D Spatial Information using aerial photographs was introduced, lots of researches on effective generation methods and applications have been performed. Nadir and oblique imagery are acquired in a same time by Pictometry system, and then 3D positioning is processed as Multi-Looking Camera procedure. In this procedure, the number of GCPs is the main factor which can affect the accuracy of true-orthoimage. In this study, 3D positioning accuracies of true-orthoimages which had been generated using various number of GCPs were estimated. Also, the standard of GCP number and distribution were proposed.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.69-75
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• 2014

Purpose: The aim of this study was to evaluate changes of quantitative and semi-quantitative myocardial perfusion indices and image quality by image reconstruction methods in $^{13}N$-ammonia ($^{13}N-NH_3$) myocardial perfusion PET/CT. Materials and Methods: Data of 14 (8 men, 6 women) patients underwent rest and adenosine stress $^{13}N-NH_3$ PET/CT (Biograph TruePoint 40 with TrueV, Siemens) were collected. Listmode scans were acquired for 10 minutes by injecting 370MBq of $^{13}N-NH_3$. Dynamic and static reconstruction was performed by use of FBP, iterative2D (2D), iterative3D (3D) and iterative TrueX (TrueX) algorithm. Coronary flow reserve (CFR) of dynamic reconstruction data, extent(%) and total perfusion deficit (TPD) (%) measured in sum of 4-10 minutes scan were evaluated by comparing with 2D method which was recommended by vendor. The image quality of each reconstructed data was compared and evaluated by five nuclear medicine physicians through a blind test. Results: CFR were lower in TrueX 18.68% (P=0.0002), FBP 4.35% (P=0.1243) and higher in 3D 7.91% (P<0.0001). As semi-quantitative values, extent and TPD of stress were higher in 3D 3.07%p (P=0.001), 2.36%p (P=0.0002), FBP 1.93%p (P=0.4275), 1.57%p (P=0.4595), TrueX 5.43%p (P=0.0003), 3.93%p (P<0.0001). Extent and TPD of rest were lower in FBP 0.86%p (P=0.1953), 0.57%p (P=0.2053) and higher in 3D 3.21%p (P=0.0006), 2.57%p (P=0.0001) and TrueX 5.36%p (P<0.0001), 4.36%p (P<0.0001). Based on the results of the blind test for image resolution and noise from the snapshot, 3D obtained the highest score, followed by 2D, TrueX and FBP. Conclusion: We found that quantitative and semi-quantitative myocardial perfusion values could be under- or over-estimated according to the reconstruction algorithm in $^{13}N-NH_3$ PET/CT. Therefore, proper dynamic and static reconstruction method should be established to provide accurate myocardial perfusion value.

• Bulletin of the Korean Mathematical Society
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• v.29 no.1
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• pp.137-143
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• 1992

The purpose of this paper is to provide the affirmative solution of the following conjecture due to Davis and Geramita. Conjecture; Let A=R[T] be a polynomial ring in one variable, where R is a regular local ring of dimension d. Then maximal ideals in A are complete intersection. Geramita has proved that the conjecture is true when R is a regular local ring of dimension 2. Whatwadekar has rpoved that conjecture is true when R is a formal power series ring over a field and also when R is a localization of an affine algebra over an infinite perfect field. Nashier also proved that conjecture is true when R is a local ring of D[ $X_{1}$,.., $X_{d-1}$] at the maximal ideal (.pi., $X_{1}$,.., $X_{d-1}$) where (D,(.pi.)) is a discrete valuation ring with infinite residue field. The methods to establish our results are following from Nashier's method. We divide this paper into three sections. In section 1 we state Theorems without proofs which are used in section 2 and 3. In section 2 we prove some lemmas and propositions which are used in proving our results. In section 3 we prove our main theorem.eorem.rem.

• ETRI Journal
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• v.40 no.6
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• pp.693-698
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• 2018

This paper presents a true-time delay (TTD) using a commercial $0.13-{\mu}m$ CMOS process for wideband phased-array antennas without the beam squint. The proposed TTD consists of four wideband distributed gain amplifiers (WDGAs), a 7-bit TTD circuit, and a 6-bit digital step attenuator (DSA) circuit. The T-type attenuator with a low-pass filter and the WDGAs are implemented for a low insertion loss error between the reference and time-delay states, and has a flat gain performance. The overall gain and return losses are >7 dB and >10 dB, respectively, at 2 GHz-18 GHz. The maximum time delay of 198 ps with a 1.56-ps step and the maximum attenuation of 31.5 dB with a 0.5-dB step are achieved at 2 GHz-18 GHz. The RMS time-delay and amplitude errors are <3 ps and <1 dB, respectively, at 2 GHz-18 GHz. An output P1 dB of <-0.5 dBm is achieved at 2 GHz-18 GHz. The chip size is $3.3{\times}1.6mm^2$, including pads, and the DC power consumption is 370 mW for a 3.3-V supply voltage.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.3
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• pp.193-197
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• 2013

This paper presents a 5-bit true time delay circuit using a standard 0.18 ${\mu}m$ CMOS process for the broadband phased array antenna without the beam squint. The maximum time delay of ~106 ps with the delay step of ~3.3 ps is achieved at 5-20 GHz. The RMS group delay and amplitude errors are < 1 ps and <2 dB, respectively. The measured insertion loss is <27 dB and the input and output return losses are <12 dB at 5-15 GHz. The current consumption is nearly zero with 1.8 V supply. The chip size is $1.04{\times}0.85\;mm^2$ including pads.

• Journal of Information Technology Applications and Management
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• v.19 no.1
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• pp.13-24
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• 2012

Usability and knowledge drawn from utilizing various ways of representing accounting data were examined. Classroom experiments were conducted to compare students' assessment of financial data using table of numbers, 2-dimensional column graphs (2D), 3-dimensional column graphs (3D), and mixed reality visualization of true 3-dimensional graphs (MR). The results showed that in assessing the financial status and performance of a firm, Table of numbers and MR took longer than 2D and 3D graphs. The time spent on true 3D graphs using MR technology was about the same as Table of numbers. When compared the assessment scores of the firm's financial status and performance between participants and experts, the difference was the least when participants used 2D graphs. However, MR was seen as being a new way to provide data of greater complexity and was very useful for financial information.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.5
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• pp.444-460
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• 2009

In this paper, we propose an expanded patching technique in order to reduce the server network bandwidth requirements to support true VoD services in VoD Systems. Double Patching, which is a typical multicast technique, ensures that a long patching stream delivers not only essential video data for the current client but also extra video data for future clients. Since the extra data may include useless data, it results in server network bandwidth wastage. In order to prevent a server from transmitting useless data, the proposed patching technique uses a new kind of stream called a linking stream. A linking stream is transmitted to clients that have received short patching streams, and it plays a linking role between a patching stream and a regular stream. The linking stream enables a server to avoid transmitting unnecessary data delivered by a long patching stream in Double Patching, so the server never wastes its network bandwidth. Mathematical analysis shows that the proposed technique requires less server network bandwidth to support true VoD services than Double Patching. Moreover, simulation results show that it has better average service latency and client defection rate compared with Double Patching.