• Journal of Mechanical Science and Technology
• /
• 제20권12호
• /
• pp.2034-2042
• /
• 2006

In this study, a complete 3D surface reconstruction method is proposed based on the concept that the vertices, of surface model can be completely matched to the unstructured point cloud. In order to generate the initial mesh model from the point cloud, the mesh subdivision of bounding box and shrink-wrapping algorithm are introduced. The control mesh model for well representing the topology of point cloud is derived from the initial mesh model by using the mesh simplification technique based on the original QEM algorithm, and the parametric surface model for approximately representing the geometry of point cloud is derived by applying the local subdivision surface fitting scheme on the control mesh model. And, to reconstruct the complete matching surface model, the insertion of isolated points on the parametric surface model and the mesh optimization are carried out. Especially, the fast 3D surface reconstruction is realized by introducing the voxel-based nearest-point search algorithm, and the simulation results reveal the availability of the proposed surface reconstruction method.

• Journal of Information Processing Systems
• /
• 제15권3호
• /
• pp.538-549
• /
• 2019

Cloud computing is the concept of providing information technology services on the Internet, such as software, hardware, networking, and storage. These services can be accessed anywhere at any time on a pay-per-use basis. However, storing data on servers is a challenging aspect of cloud computing. This paper utilizes cryptography and access control to ensure the confidentiality, integrity, and proper control of access to sensitive data. We propose a model that can protect data in cloud computing. Our model is designed by using an enhanced RSA encryption algorithm and a combination of role-based access control model with extensible access control markup language (XACML) to facilitate security and allow data access. This paper proposes a model that uses cryptography concepts to store data in cloud computing and allows data access through the access control model with minimum time and cost for encryption and decryption.

• 한국IT서비스학회지
• /
• 제10권3호
• /
• pp.149-166
• /
• 2011

While the importance of adopting cloud computing service has been emerged, comparatively little research has been conducted on examining factors of an individual user's intention to switch toward cloud computing service. Hereafter, this study presents and empirically tests users' intention to switch to cloud computing. Our model posits that the characteristics of cloud computing such as collaboration support, accessability, trust to cloud service affect perceived value, which in turn, influences intention to switch. An experimental study using student subjects provided empirical validation for our proposed model. Survey data from 106 respondents was used to test the model using partial least square analysis. According to our results, the characteristics of cloud computing were found to have significant impact on users' intention to switch that partially mediated by perceived value. Based on our research findings, we hope that this research will stimulate researchers' interest in the emerging area of cloud computing adoption.

• 융합보안논문지
• /
• 제17권3호
• /
• pp.15-20
• /
• 2017

클라우드 컴퓨팅은 인터넷이 가능한 환경에서 다양한 단말을 통해 IT 자원(소프트웨어, 스토리지, 서버, 네트워크)을 이용할 수 있는 서비스이다. 편리성과 효율성, 비용 절감의 이유로 최근 이용률이 급증하였다. 하지만 정보의 집중화로 인해 범죄의 표적이 되거나 클라우드 서비스를 악용하는 범죄가 발생하였다. 기존 디지털 포렌식 절차는 개인 단말기를 대상으로 하는 수사에 적합하다. 본 논문은 기존 디지털 포렌식 수사 절차로 클라우드 환경을 조사할 경우 발생하는 취약점들을 분석하여 새로운 수사 모델을 제안하였다. 제안된 수사 모델은 계정정보를 획득할 수 있는 방법을 추가하였으며, 공공 클라우드와 사설클라우드를 아울러 적용할 수 있다. 또한, 클라우드 서비스는 쉽게 접근이 가능하여 디지털 증거 인멸 가능성이 높기에 계정 접근 차단 단계를 추가함으로써 수사 모델을 보강하였다.

• 대한원격탐사학회지
• /
• 제6권1호
• /
• pp.11-24
• /
• 1990

This is the study about the meteorological satellite cloud image classification by objective methods. For objective cloud classification, linear discriminant analysis was tried. In the linear discriminant analysis 27 cloud characteristic parameters were retrieved from GMS infrared image data. And, linear cloud classification model was developed from major parameters and cloud type coefficients. The model was applied to GMS IR image for weather forecasting operation and cloud image was classified into 5 types such as Sc, Cu, CiT, CiM and Cb. The classification results were reasonably compared with real image.

• 한국IT서비스학회지
• /
• 제12권4호
• /
• pp.1-23
• /
• 2013

This study examines whether key characteristics of cloud computing services would affect the intention of use for personalized cloud computing services. The research model was generated based on Technology Acceptance Model (TAM) with resistance variable, and verified statistically by undertaking a survey about the perception of personal users. As the results of this analysis, we could find the structural relationship among the factors affecting adoption of the cloud computing service. We found that the expectation of ubiquity as a representative function of the cloud computing service meaningfully affected the perceived ease of use and resistance, and that the relativeness with existing services also meaningfully affected the perceived ease of use, but not the resistance. In addition, the moderating effects of use experience in the path leading from the perceived ease of use and resistance to the intention of use were identified. This study will provide diverse implications for the companies providing personalized cloud computing services.

• 한국대기환경학회지
• /
• 제6권2호
• /
• pp.176-182
• /
• 1990

A one dimensional cumulus cloud model has been developed to investigate the size distribution of hydrometeors at different heights and at different stages of cloud development. The model results show that the exponential distribution of droplet radius that was employed by many investigators can misinterpret the cloud dynamic fields during the life cycle of cumulus cloud. The results also show the bimodal distribution of cloud water mixing ratios at 25 $\mu$m and 645 $\mu$m in radius at 45 minutes of simulation time. The developed model can be applied in future on the parameterization of cloud microphysical processes and air pollution models.

• 대기
• /
• 제22권1호
• /
• pp.73-85
• /
• 2012

The collision efficiency data for collision between graupel or hail particles and cloud drops that take into account the differences of particle density are applied to the Takahashi cloud model. The original setting assumes that graupel or hail collision efficiency is the same as that of the cloud drops of the same volume. The Takahashi cloud model is run with the new collision efficiency data and the results are compared with those with the original. As an initial condition, a thermodynamic profile that can initiate strong convection is provided. Three different CCN concentration values and therefore three initial cloud drop spectra are prescribed that represent maritime (CCN concentration = 300 $cm^{-3}$), continental (1000 $cm^{-3}$) and extreme continental (5000 $cm^{-3}$) air masses to examine the aerosol effects on cloud and precipitation development. Increase of CCN concentration causes cloud drop sizes to decrease and cloud drop concentrations to increase. However, the concentration of ice particles decreases with the increase of CCN concentration because small drops are difficult to freeze. These general trends are well captured by both model runs (one with the new collision efficiency data and the other with the original) but there are significant differences: with the new data, the development of cloud and raindrop formation are delayed by (1) decrease of ice collision efficiency, (2) decrease of latent heat from riming process and (3) decrease of ice crystals generated by ice multiplication. These results indicate that the model run with the original collision efficiency data overestimates precipitation rates.

• 정보보호학회논문지
• /
• 제25권5호
• /
• pp.1245-1255
• /
• 2015

클라우드 컴퓨팅의 성장과 더불어 클라우드 이용자 데이터 보안에 대한 우려가 증가하고 있으므로 이러한 우려를 감소시키는 것이 클라우드 컴퓨팅에서 필수적이다. 본 논문에서는 클라우드 컴퓨팅에 대한 정의 및 장단점을 설명하고 클라우드 컴퓨팅 발전법에서 정의하고 있는 이용자 정보 보호 규정에 대해 논한다. 다음으로 클라우드에서의 개인정보 보호 논점 및 개인정보 위 수탁에 관한 기존 연구 내용을 살펴본다. 그리고, 클라우드 서비스 유형에 따른 개인정보 저장 방식의 차이를 살펴보고 이로 인해 클라우드 서비스 별로 개인정보의 위 수탁 관계가 달라져야 함을 논한다. 이를 바탕으로 IaaS와 SaaS 클라우드 서비스 유형별로 개인정보를 보호하는 방안을 제안한다.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 1996년도 학술발표회
• /
• pp.37-42
• /
• 1996

The assessment of catastrophic accidents such as BLEVE, vapor cloud explosion, and toxic material releases in the chemical process industries(CPI) shall be carried out according to the Requirement of PSM/SMS enforced by Korea Government Agencies, but reasonable models are not proposed for the practical application. The traditional models, TNT Equivalency Model, are well-known and helpful for the assessment of vapor cloud explosion. However, the estimated-damage-area using the traditional model has much more deviations comparing to the real damage caused by vapor cloud explosion suffered before. These are why an expert system for the assessment of vapor cloud explosion has been developed, which is based on theoretical, statistical and experimental data, and it would be helpful for CPI to evaluate the damage-area in case of vapor cloud explosion.