• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.153-169
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• 2017

The purpose of this study was to determine a suitable site using GIS for solar energy harvesting for an administrative district in Daegu, which aims at becoming a solar-powered city. From this result, the ecological housing complex was planned on a solar theme in the real site. For this analysis, various indicators and standards were selected based on previous studies and the indicators were divided into the location, exclusion, and class condition. The results showed that the suitable area was $153.95km^2$ and 17.6% for Daegu area, and the highest suitable area appeared to Dalseong-gun. Finally, using suitable site analysis results, we selected the site of Sinseo housing area in Dong-gu and we planned the ecological housing complex for solar energy. This study can be used as base data for the Daegu solar business and its establishment by considering various indicators for analysis of suitable areas in solar energy. Also, the result of the ecological housing complex plan would be helpful in promoting Daegu as a solar-powered city.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.1
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• pp.53-62
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• 2017

In this paper, we present the score classification accuracy of BBS(Berg Balance Scale) which is the most commonly used balance evaluation tool using machine learning. Data acquisition was performed using the Noraxon system and an inertial sensor of Noraxon system was attached to the body in 8 locations (left and right ankle, left and right upper buttocks, left and right wrists, back, forehead). Based on the 3-axis accelerometer of the inertial sensor, the feature vector STFT(Short Time Fourier Transform) and SAM(Signal Area Magnitude) were extracted. Then, the items of the BBS were divided into static movement and dynamic movement depending on the operation characteristics, and the feature vectors were selected according to the sensor attachment positions which affect the score for each item of the BBS. Feature vectors selected for each item of BBS were classified using GMM(Gaussian Mixture Model). As a result of the accuracy calculation for 40 subjects, 55.5%, 72.2%, 87.5%, 50%, 35.1%, 62.5%, 43.3%, 58.6%, 60.7%, 33.3%, 44.8%, 89.2%, 51.8%, 85.1%, respectively.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.203-211
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• 2008

Due to the advance of H/W and S/W techniques to play 3D sound, the virtual space contented by 3D graphics and sounds can provide users more improved realities and vividness. However for the small 3D contents developers and companies, it is hard to implement 3D sound techniques because the implementation requires expensive sound engines, 3D sound technical understanding and 3D sound programming skills. Therefore 3D-sound-playing-interface is necessary to easy and cost-effective 3D sound implementation. Using this interface, graphics experts can easily add 3D sound techniques to their applications. In this paper, the followings are designed and implemented as a preliminary stage in the way of developing the 3D sound playing interface. First, we develop 3D sound S/W modules converting mono to 3D sound in PC based systems. Second, we develop the interconnection modules to map 3D graphic objects and sound sources. The developed modules in this paper can allow the user to percept sound source position and surround effect at the moving positions in the virtual world. In the coming works, we are going to develop the more completed 3D sound playing interface consisted of the synchronization technique for sound and moving objects, and HRTF.

• Radiation Oncology Journal
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• v.29 no.2
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• pp.99-106
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• 2011

Purpose: To analyze our quality assurance (QA) data for intensity modulated radiation therapy (IMRT) according to treatment site and to possibly improve QA for IMRT in Hospital. Materials and Methods: We performed QA on 50 patients (head and neck, 28 patients; Breast, 14 patients; Pelvis, 8 patients) for IMRT. The calculated dose from RTP was compared with the measured value film, gamma index, and ionization chamber for dose measurement in each case. Results: The point dose measurement results in 45 of 50 patients showed good agreement with the calculation dose (${\pm}3%$). The largest error measured thus far has been 3.60%, with a mean of only -0.17% (SD, 2.25%). Each treatment site showed an error rate of -0.13% (SD, 1.93%) for head and neck cases, -0.26% (SD, 2.79%) for breast cases, and 0.24% (SD, 2.44%) for pelvis cases. The gamma index verified with the error rate of head and neck cases (6%), breast (10%), and pelvis (6%), which corresponded to a tolerance of 3 mm (3% for the head and neck, 2%, for the breast 1% for the pelvis, and 0% in the region where the isodose curve was greater than 90%. Conclusion: We recognize the cause of errors for each treatment site of IMRT QA and so we maximize our efforts to reduce error and increase accuracy.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1189-1193
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• 2010

Mobility management is one of the most important research issues in 6LoWPAN, Since the IP-WSN application domain is expanded to real-time applications such as healthcare and surveillance systems, a fast and seamless handover becomes an important criterion in 6LoWPAN. However, a draft of IETF 6LoWPAN WG for mobility support does not decrease handover delay. Although LoWMob supports a fast intra-PAN handover. it can be supported when the infrastructure node has the location information of the other nodes in the mobile node's moving direction. In this paper, we propose a fast and seamless mobility protocol to support intra-PAN handover, named intra-MARIO. In intra-MARIO, a parent node of the mobile node preconfigures its handover to the PAN when the parent node detects its movement, thereby reducing the handover delay. Since intra-MARIO also supports route optimization, the mobile node can communicate with its corresponding nodes through the optimal route. In this paper, we analysis the signaling cost and evaluates that the handover can be completed in 20ms by simulation.

• The KIPS Transactions:PartB
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• v.9B no.3
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• pp.375-382
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• 2002

Handwritten character recognition is classified into on-line handwritten character recognition and off-line handwritten character recognition. On-line handwritten character recognition has made a remarkable outcome compared to off-line hacdwritten character recognition. This method can acquire the dynamic written information such as the writing order and the position of a stroke by means of pen-based electronic input device such as a tablet board. On the contrary, Any dynamic information can not be acquired in off-line handwritten character recognition since there are extreme overlapping between consonants and vowels, and heavily noisy images between strokes, which change the recognition performance with the result of the preprocessing. This paper proposes a method that effectively extracts the stroke including dynamic information of characters for off-line Korean handwritten character recognition. First of all, this method makes improvement and binarization of input handwritten character image as preprocessing procedure using watershed algorithm. The next procedure is extraction of skeleton by using the transformed Lu and Wang's thinning: algorithm, and segment pixel array is extracted by abstracting the feature point of the characters. Then, the vectorization is executed with a maximum permission error method. In the case that a few strokes are bound in a segment, a segment pixel array is divided with two or more segment vectors. In order to reconstruct the extracted segment vector with a complete stroke, the directional component of the vector is mortified by using right-hand writing coordinate system. With combination of segment vectors which are adjacent and can be combined, the reconstruction of complete stroke is made out which is suitable for character recognition. As experimentation, it is verified that the proposed method is suitable for handwritten Korean character recognition.

• The KIPS Transactions:PartA
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• v.15A no.3
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• pp.141-149
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• 2008

In this research we present a novel method which combines and visualizes the design model and the FDM-based simulation result of solidification. Moreover we employ VR displays and visualize stereoscopic images to provide an effective analysis environment. First we reconstruct the solidification simulation result to a rectangular mesh model using a conventional simulation software. Then each point color of the reconstructed model represents a temperature value of its position. Next we map the two models by finding the nearest point of the reconstructed model for each point of the design model and then assign the point color of the design model as that of the reconstructed model. Before this mapping we apply mesh subdivision because the design model is composed of minimum number of points and that makes the point distribution of the design model not uniform compared with the reconstructed model. In this process the original shape is preserved in the manner that points are added to the mesh edge which length is longer than a predefined threshold value. The implemented system visualizes the solidification simulation data on the design model, which allows the user to understand the object geometry precisely. The immersive and realistic working environment constructed with use of VR display can support the user to discover the defect occurrence faster and more effectively.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.443-450
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• 2018

The Geant 4 simulated the linear accelerator (VARIAN CLINAC) based on the previously implemented BEAMnrC data, using the head structure of the linear accelerator. In the 10 MV photon flux, Geant4 was compared with the measured value of the percentage of the deep dose and the lateral dose of the water phantom. In order to apply the dose calculation to the body part, the actual patient's lung area was scanned at 5 mm intervals. Geant4 dose distributions were obtained by irradiating 10 MV photons at the irradiation field ($5{\times}5cm^2$) and SAD 100 cm of the water phantom. This result is difficult to measure the dose absorbed in the actual lung of the patient so the doses by the treatment planning system were compared. The deep dose curve measured by water phantom and the deep dose curve calculated by Geant4 were well within ${\pm}3%$ of most depths except the build-up area. However, at the 5 cm and 20 cm sites, 2.95% and 2.87% were somewhat higher in the calculation of the dose using Geant4. These two points were confirmed by the geometry file of Genat4, and it was found that the dose was increased because thoracic spine and sternum were located. In cone beam CT, the dose distribution error of the lungs was similar within 3%. Therefore, if the contour map of the dose can be directly expressed in the DICOM file when calculating the dose using Geant4, the clinical application of Geant4 will be used variously.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.4
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• pp.316-322
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• 2012

In the port of Ulsan with the area of harbor limit of $83km^2$, 25,432 vessels have been entering annually and only 35 vessels can anchor simultaneously at the anchorage. The area of harbor limit of Ulsan constitutes just 65 percent compared to $127.5km^2$ which is an average of main ports in Korea. In this regard, the port of Ulsan needs to expand the area of anchorages inevitably for enhancing the efficiency of port operation. To select the best anchorage area in Mipo harbor with the introduction of a concept of emergency anchorage, this study analyzed the safety of navigation and anchorage, and safety management, etc. in the prospected anchorage on the basis of the marine traffic survey observing traffic density. Furthermore, after drawing preliminary and final schemes through gathering the opinions from maritime users, safety management organizations and academic experts group, the best arrangement of emergency anchorage has been selected through the conference of interested parties. Then, the final scheme was also verified through figuring out the marine traffic system and carrying out the ship handling simulation.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.147-154
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• 2006

The certificate status validation mechanism is a critical component of a public key infrastructure based on certificate system. The most generally mechanisms used these days are the use of the certificate revocation list and the real-time certificate status protocol. But the certificate revocation list can not give the real-time certificate status because the certificate is being delivered periodically, and the real-time certificate status protocol method will generate a concentrated load to the server because the protocol in the central server will be accessed whenever a certification is necessary. It will also take a long time to validate the certificate because each trade has to send mass information through the network. This paper will present that real-time validation is guaranteed as the real-time certificate status protocol method and the traffic congestion in the network Is reduced in a way that the certification would be requested using the user information hash value and would be validated using the user information kept in the certification authorities and the service providers. Based on the this study, we suggest a real-time certificate status validation mechanism which can reduce the certificate status validation time using the signed user information hash value. And we confirm speed of certificate status verification faster than existing CRL(Certificate Revocation List) and OCSP(Online Certificate Status Protocol) method by test.