다단계 보안 데이테베이스 시스템을 위한 제한적 버전관리 거래 조정 기법

손용락 서경대학교 1996 論文集 Vol.24 No.-

As multilevel secure database management systems become read and in use today, secure concurrency control schemes for sunchronizing concurrent transactions are receiving a lot of interest and much work has been done. Although previous works achieve the confidentiality successfully, however, some of them overlook the integrity and the rest of them overlook the availability. For being evaluated as highly secure computing system, the multilevel secure database management systems inevitably achieve the confidentiality, integrity, and the avaialbility that are the well-known major aspects of security. For achieving the aspects of security altogether, this paper suggests a new secure concurrency control scheme, called CIA/CC(Confidentiality, Integrity, Availability/Concurrency Control), that is founded on multiversion database. By eliminating the covert channel that may occur while synchronizing the conflicting transactions that have been cleared at different confidentiality levels, CIA/CC achieves the confidentiality. Moreover, by ensuring the correctness of a history that has been produced by CIA/CC, CIA/CC also achieves the integrity. As CIA/CC has been founded on the multiversion database, maintaining multiversions are inevitable. Hence, with active version replacement strategies, it always maintains the bounded number of versions. When a conflict occurs between different availability level transactions, CIA/CC achieves the availability by selecting a transaction whose availability level is the lower than that of the other transaction's as the transaction to be aborted.

신뢰성에 기초한 PC빔교의 내하력 평가

백용락,정인수,신재철,이상국 忠南大學校 産業技術硏究所 1996 산업기술연구논문집 Vol.11 No.2

In most countries road bridges are subjected to increasingly heavy freight traffic with a number of exceptional truck loads. This has made it necessary to devote particular attention to the evaluation of safety and load-carrying capacity of bridges, which is a vital process in the decision-making for maintenance, repair, strengthening, or even replacement of existing road bridges. However, most countries including Korea do not have a comprehensive rating system or rating code. Furthermore, the current methods of rating of road bridges are dependent on the conventional design concepts and the safety parameters of the current bridge design codes. A practical reliability model for the safety assessment and rating of existing PC beam bridges are developed by explicitly incorporating the degree of deterioration and damages based on available inspection or field test data. AFOSM methods are used for the reliability analysis of the proposed models. The proposed reliability model and methods are applied to the safety assessment of existing PC beam bridges in Korea.

Kodak 649F Plates를 이용한 Dichromated Gelatin 홀로그래픽 감광재 처리 방법 연구

임용석,이영락,최옥식 嶺南大學校 基礎科學硏究所 1995 基礎科學硏究 Vol.15 No.-

Dichromated gelatin plays an important role to fabricate various kinds of holographic optical elements. In this study, we have investigated the processing method and the characteristics of dichromated gelatin recording materials by using Kodak 649F plates. The processing methods for obtaining high diffraction efficiencies and environmental stability which are necessary for the fabrication of the holographic optical elements are presented. Exposure characteristics, spectral and angular sensitivity, and the degradation of the diffraction efficiency versus time are measured. The maximum diffraction efficiency of the obtained holographic grating is about 90%.

사고압력 조건에서 기하학적 특성을 고려한 원자로 격납건물 거동해석

백용락,신재철 忠南大學校 産業技術硏究所 1996 산업기술연구논문집 Vol.11 No.1

In this study, effects of the representative geometrical feature of a reactor containment structure on the structural responses for accident pressure are analyzed. The analysis is carried out for the containment structure of YongGwang unit 3 & 4, which is a standardized nuclear power plant in Korea. The representative geometry of the structure such as buttress, opening and reinforced section surrounding the opening is considered as a variable in the analysis. The analysis results show that the geometrical effects on the responses are significant. From the results, the essential consideration items in the analysis of the structure for accident pressure are derived for comparison of the analysis and the test results, and items to be improved are proposed to establish a plan for measuring the exact responses in case of structural integrity test (SIT) of the structure. The adequacy of the two-dimensional axisymmetric model for the analysis, which is a commonly used model, is investigated and the region unaffected by the geometrical feature is also estimated for constructing a partial model of the structure for the detailed design of the section near a equipment hatch.

질소분압에 따른 TaNx coating층의 미세조직 연구

김선화,최용락 순천향대학교 부설 산업기술연구소 1998 순천향 산업기술연구소논문집 Vol.3 No.3

TaNx film were fabricated for this research by the reactive magnetron sputtering process. In order to improve TCR, it was investigated the transformation of coated TaNx film. The variables were the N₂/Ar fraction and the thermal heat-treatment. The electrical resistance and the TCR of specimen were measured. It was observed the microstructure change under thermal heat-treatment by XRD experiment. Also the morphology of TaNx film was observed by SEM. As a result, TCR was stabilized when N₂/Ar fraction were 0.166 to 0.25. The phases of as-coated TaNx film were Ta, TaN, β-Ta and amorphous. The new phases, Ta₄N and Ta₃N?? were formed after thermal heat-treatment. As the ratio of nitrogen gas was increased, the morphology of the layer was changed to a discontinuous island particle. These results were consistent with results of electrical resistance change.

칠절봉 신갈나무(Quercus mongolica)림의 군락구조와 토양환경

이호준,배병호,전영문,정흥락,홍문표,김용옥,길지현 建國大學校基礎科學硏究所 1998 理學論集 Vol.23 No.-

칠절봉 신갈나무림의 군락구조와 토양환경과의 관계를 파악하기 위해 식물사회학적 조사와 토양 환경을 분석하였다. 조사지역의 신갈나무림은 신갈나무군락, 철쭉꽃하위군, 큰개별꽃하위군으로 구분되었으며, 철쭉꽃하위군과 큰개별꽃하위군에서의 방형구당 평균출현종수는 각각 30종(24∼46종), 43종(31∼52종) 이었다. 피복지수치에 의한 계층별 우점순위는 교목층에서 신갈나무(6750.0), 아교목층에서 당단풍(2364.0) 관목층에서 철쭉꽃(988.5), 초본층에서 쌀새(1040.5)가 가장 높게 나타났다. 신갈 나무림의 DBH 분포는 2∼10㎝ 범위의 소경목이 전체의 29.7%를 차지하였으며 전체적으로 정규분포를 나타내어 교란 후 재생과정에 있는 것으로 조사되었다. 또한 후계목의 발달로 인한 극상상태로의 천이가 가능할 것으로 조사되었다. 전반적인 토양환경은 두 하위군 간에 뚜렷한 차이가 없었으며, 큰개별꽃하위군이 철쭉꽃하위군에 비하여 다소 양호한 것으로 조사되었다. 환경구배분석에서 까치박달, 물푸레나무, 함박꽃나무 등은 습한 곳에 분포하고 철쭉꽃, 전나무, 국수나무 등은 건조한 곳에 분포하는 것으로 나타났다. A relationship between the community structure composition and soil environmental factors of the Quercus mongolica forest on Mt. Chiljelbong was investigated from June 1996 to August 1997. The Q. mongolica community was classified into two subcommunity of Rhododendron schlippenbachii and Pseudostellaria palibiniana. The 30(24-46) species per quadrat were appeared in R. schlippenbachii subcommunity and 43(31-52)species in P. palibiniana subcommunity. The dominant sequences on each stratum determined by the coverage index showed that Q. mongolica was the most dominant in tree-1 layer with 6750.0, Acer pseudo-sieboldianum in tree-2 layer with 2364.0, R. schlippenbachii in shrub layer with 988.5, and Melica onoei in herb layer with 1040.5 value. The value of diameter breast height(DBH) showed a normal distribution displaying a highest value in the range of 2∼10㎝(29.7%) in Q. mongolica forest and it was investigated being at restoration phase after disturbance. It also was investigated that the succession to climax state would be possible due to growth of successive tree. Overall, which the soil conditions make little difference between two subcommunities, P. palibiniana subcommunity was favorable than those of R. schlippenbachii subcommunity. It was shown that in an environmental gradient analysis, Carpinus cordata, Fraxinus rhynchophylla, and Magnolia sieboldii were distributed in a mesic area, but R. schlippenbachii, Abies holophylla, and Stepanandra incisa in a xeric area.

Soldier Bugs, Bug Cannons, and Drones: Classical Biological Control with Advanced Technology

Yong-Lak Park,Srikanth Gururajan,Chang-Gyu Park,Jum Rae Cho,Bo Yoon Seo 한국응용곤충학회 2018 한국응용곤충학회 학술대회논문집 Vol.2018 No.04

The spined soldier bug, Podisus maculiventris (Hemiptera: Pentatomidae), can feed on more than 70 species of insects including immature stages of Lepidoptera and Coleoptera. P. maculiventris is native to North America and there was an attempt and failure to import P. maculiventris to South Korea in 1970s. Recently, P. maculiventris was successfully re-introduced to South Korea and is being contained and reared in a quarantined facility at the National Institute of Agricultural Sciences, Rural Development Administration, South Korea. In this presentation, we will introduce this new biological control agent targeting major lepidopteran and coleopteran pests in agriculture and forest. In addition, current research on mass rearing and aerial release of P. maculiventris using drones will be presented.

Improving Database System Performance by Applying NoSQL

( Yong Lak Choi ),( Woo Seong Jeon ),( Seok Hwan Yoon ) 한국정보처리학회 2014 Journal of information processing systems Vol.10 No.3

Internet accessibility has been growing due to the diffusion of smartphones in today``s society. Therefore, people can generate data anywhere and are confronted with the challenge that they should process a large amount of data. Since the appearance of relational database management system (RDBMS), most of the recent information systems are built by utilizing it. RDBMS uses foreign-keys to avoid data duplication. The transactions in the database use attributes, such as atomicity, consistency, isolation, durability (ACID), which ensures that data integrity and processing results are stably managed. The characteristic of RDBMS is that there is high data reliability. However, this results in performance degradation. Meanwhile, from among these information systems, some systems only require high-performance rather than high reliability. In this case, if we only consider performance, the use of NoSQL provides many advantages. It is possible to reduce the maintenance cost of the information system that continues to increase in the use of open source software based NoSQL. And has a huge advantage that is easy to use NoSQL. Therefore, in this study, we prove that the leverage of NoSQL will ensure high performance than RDBMS by applying NoSQL to database systems that implement RDBMS.

Advances, Limitations, and Future Applications of Aerospace and Geospatial Technologies for Apple IPM

Yong-Lak Park,Jum Rae Cho,Kyung-Hee Choi,Hyun Ran Kim,Ji Won Kim,Se Jin Kim,Dong-Hyuk Lee,Chang-Gyu Park,Young Sik Cho 한국응용곤충학회 2021 한국응용곤충학회지 Vol.60 No.1

항공 및 지리 공간 기술은 연구자 및 농업관련 실무자들이 더욱더 쉽게 접근할 수 있게 되었으며, 이러한 기술은 농업과 임업에 있어 현재 병해충 관리의 변화에 중추적인 역할을 할 수 있다. 지난 20년 동안 위성, 유무인항공기, 스펙트럼 센서들, 정보 시스템 및 자동화 현장 장비들의 기술들은 병해충을 감지하고, 특정 지점에 대한 병해충을 방제하는데 사용되어져 왔다. 빅 데이터 기반한 인공 지능과 함께 항공 및 지리 정보 기술의 가용 함에도 불구하고 이러한 기술을 사과 IPM에 적용하는 것은 아직 실현되지 않았다. 본 논문은 사과연구소에서 수행한 사례 연구를 통해 사과 IPM 개선에 활용할 수 있는 항공 및 지리 정보기술의 발전과 한계에 대해 논하고자 한다. Aerospace and geospatial technologies have become more accessible by researchers and agricultural practitioners, and these technologies can play a pivotal role in transforming current pest management practices in agriculture and forestry. During the past 20 years, technologies including satellites, manned and unmanned aircraft, spectral sensors, information systems, and autonomous field equipment, have been used to detect pests and apply control measures site-specifically. Despite the availability of aerospace and geospatial technologies, along with big-data-driven artificial intelligence, applications of such technologies to apple IPM have not been realized yet. Using a case study conducted at the Korea Apple Research Institute, this article discusses the advances and limitations of current aerospace and geospatial technologies that can be used for improving apple IPM.

Evolution and Mechanical Effect of S`-Phase in ECA Pressed Al-3.8Cu-1.2Mg-0.5Mn Alloys

( Yong Lak Choi ),( Seon Hwa Kim ) 대한금속재료학회 ( 구 대한금속학회 ) 2008 METALS AND MATERIALS International Vol.14 No.6

The composition, morphology, and distribution of an Al-3.8Cu-1.2Mg-0.5Mn alloy precipitate formed during the ECAP process was investigated using XRD and TEM, and its mechanical properties were estimated via a SP test. A texture structure was formed at the initial state of the ECAP process, but an equiaxed structure was formed as the process progressed. The grain size was refined to around 100 nm through the ECAP process, and the morphology of the S` phase at the initial state is characterized by a rod shape in the grain boundary. As the number of passes increased, the S` phase assumed a spherical shape, with a diameter of 10 nm to 20 nm, and it was uniformly distributed in the internal grain boundary. Growth of the S` phase was also observed, and is thought to be due to Ostwald ripening. The results of the SP test show that the maximum load increased to above 60 %, indicating that changes in the size and distribution of the S` phase affect the alloy`s tensile strength.