주소 관련 미래 산업의 확장으로 새로운 주소체계에 대한 수요가 증가하였으며, 특정 사물에 주소를 부여하는 체계인 사물주소의 중요성이 강조되고 있다. 현행 사물주소는 행정안전부가 제작 및 배포하고 있으며 데이터베이스 제작 등 사물주소의 활성화를 위한 노력이 지속되고 있다. 하지만 현행 사물주소는 하향식 방법으로 부여되고 있기 때문에 수요자 응답형 정보제공 대응에 미흡한 현실이다. 이에 본 연구에서는 상향식 방법으로 운영 중인 포켓몬 고 DB와 사물주소 DB의 공간적 분포를 탐색함으로 써 사용자 참여형 주소정보 생성 및 적용 가능성을 제시하였다. 각 DB의 지점별 티센 폴리곤을 생성한 뒤 ANOVA 분석을 수행한 결과 두 DB간의 면적 차이가 있음을 확인하였다. 또한 지니 계수를 산출하여 분포 불평등성을 확인하여 DB를 통합하여 활용하는 방법을 제시하였다. 본 연구는 사물주소의 확산과 알기 쉬운 대국민 주소정보체계 확립에 정책적인 활용이 가능할 것이다.
Since interstellar objects like 1I/`Oumuamua and 2I/Borisov originate from exoplanetary systems, evenif we do not visit the exoplanetary systems,yby, rendezvous, and sample return missions of interstellarobjects can provide clues to solve the mysteries of cosmic life phenomena such as the origin of exoplanetarysystems, galactic evolution, biosignatures (or even technosignatures), and panspermia. In this paper, wereview space missions for interstellar object exploration in the stage of mission design or concept studysuch as Project Lyra, Bridge, Comet Interceptors, and LightcraftTM. We also review space missions,OSIRIS-REx and NEA Scout, designed for Near Earth Asteroids(NEA) explorations, to investigate thecurrent state of basic technologies that can be extended to explore interstellar objects in a velocity of~ 6AU/year. One of the technologies that needs to be developed for interstellar object exploration is aspacecraft propulsion method such as solar sail, which can catch up with the fast speed of interstellarobjects. If this kind of propulsion becomes practical for space explorations, interstellar object explorationswill mark a new era and serve as a driving force to provide evidences of cosmic life.
In this study, an incremental loading test of the HRS(Hybrid Rubber Slit) damper was additionally performed to define the physical characteristics according to the incremental test results, and an analytical study was performed according to the damping design procedure by selecting an example structure. As a result of performing seismic performance evaluation before reinforcement by selecting a RC structure similar to an actual school structure as an example structure, the story drift ratio was satisfied, but some column members collapsed due to bending deformation. In order to secure the seismic performance, the damping design procedure of the HRS damper was presented and performed. As a result of calculating the amount of damping device according to the expected damping ratio and applying it to the example structure, the hysteresis behavior was stable without decrease in strength, and the story drift ratio and the shear force were reduced according to the damping effect. Finally the column members that had collapsed before reinforcement satisfied the LS Level.
It is effective to apply hybrid damping device that combine separate damping device to cope with various seismic load. In this study, HRS hybrid damper(hybrid rubber slit damper) in which high damping rubber and steel slit plate are combined in parallel was proposed and structural performance tests were performed to review the suitability for seismic performance. Cyclic Loading tests were performed in accordance with criteria presented in KDS 41 17 00 and MOE 2019. As a result of the test, the criteria of KDS 41 17 00 and MOE2019 was satisfied, and the amount of energy dissipation increased due to the shear deformation of the high-damping rubber at low displacement. Result of performing the RC frame test, the allowable story drift ratio was satisfied, and the amount of energy dissipation increased in the reinforced specimen compared to the non-reinforced specimen.
Today, as technology advances and market competition for products intensifies, the design to improve product satisfaction by accurately identifying customer requirements is emerging as a very important problem for company. Accordingly, Customer-Oriented Design, that maximizes customer satisfaction by grasping and analyzing customer requirements, is in the spotlight as an important design theory. In this study, Customer- Oriented Design is defined as finding the optimal value of the design variable with the maximum overall customer satisfaction while minimizing the difference in individual customer satisfaction responded to various customers from multiple product quality characteristics from the perspective of robust design. Therefore, in this work, we present a new method for generating a Desirability Function for each quality characteristic to deal with the multi characteristic parameter design with multiple quality characteristics. And we propose a new Customer-Oriented Design methodology that applies these Desirability Functions to Taguchi’s parameter design process.
To investigate the tolerance limit and critical thermal maximum (CTM), behavioral responses of wild goldeye rockfish Sebastes thompsoni according to exposure to high water temperature were observed using a continuous behavior tracking system. As a result, behavioral index (BI) of S. thompsoni in each temperature (20.0, 25.0, and 30.0°C) showed a significant difference (p<0.05) when compared with the value measured in a stable condition of 15.0°C. The activity level of S. thompsoni exposed to 25.0°C decreased sharply after 20 hours. Their rest time at the bottom of experiment chamber increased, and their normal swimming and metabolic activities were disturbed. In addition, at a high water temperature of 30.0°C, S. thompsoni reached the limit of resistance and showed a sub-lethal reaction of swimming behavior, with energy consumption in the body increased and all test organisms died. In conclusion, the eco-physiological response of S. thompsoni to water temperature varied greatly depending on the fluctuation range of the exposed temperature and the exposure time. In addition, the tolerance limit of S. thompsoni to high water temperature was predicted to be 25.0- 30.0°C. The maximum critical thermal that had a great influence on the survival of this species was found to be around 30.0°C.
This study investigates the interfacial reaction between powder-metallurgy high-entropy alloys (HEAs) and cast aluminum. HEA pellets are produced by the spark plasma sintering of Al0.5CoCrCu0.5FeNi HEA powder. These sintered pellets are then placed in molten Al, and the phases formed at the interface between the HEA pellets and cast Al are analyzed. First, Kirkendall voids are observed due to the difference in the diffusion rates between the liquid Al and solid HEA phases. In addition, although Co, Fe, and Ni atoms, which have low mixing enthalpies with Al, diffuse toward Al, Cu atoms, which have a high mixing enthalpy with Al, tend to form Al–Cu intermetallic compounds. These results provide guidelines for designing Al matrix composites containing high-entropy phases.
본 연구에서는 액체감쇠역전회복(FLAIR) 시퀀스를 대체하였던 방법 중에 비교적 간단하면서 높은 재현성을 나타내었던 고신호 강도제거 원리를 MAGiC에 적용하여 MAGiC-FLAIR와 기존의 고속스핀에코-FLAIR 영상과 비교하여 고신호 강 도제거영상의 유용성과 임상적으로 유의미한 기준을 제시하고자 하였다. 연구방법은 MAGiC 적용 후 MAGiC-FLAIR와 MAGiC-고신호 강도제거 영상을 재구성하여, 기존의 고속스핀에코-FLAIR 영상과 각각 정성적, 정량적 평가를 비교하였 다. 정성평가결과 MAGiC-고신호 강도제거는 MAGiC-FLAIR 보다는 월등히 우수하며, 고속스핀에코-FLAIR와 유사한 결과를 보였고, 정량평가결과 MAGiC-고신호강도제거는 MAGiC-FLAIR보다 백질과 회백질 대조도는 더 우수할 뿐만 아 니라, 뇌척수액의 신호 억제도 우수한 결과를 나타냈다. Synthetic 영상을 통하여 획득한 다양한 대조도 영상 중 FLAIR의 부정확도를 고신호 강도제거기법을 적용한다면 진단적 가치를 개선하여 제공할 수 있을 것이다.
Porous ceramics have the advantages of low density, low thermal conductivity, and excellent mechanical properties. Among porous ceramic manufacturing methods, the replica template method allows the easy manufacturing of porous filters with the highest porosity and pores of the desired size, but it also has the disadvantage that the resulting filters have low mechanical strength. To overcome this shortcoming, mullite (3Al2O3·2SiO2) whiskers, which have excellent thermal stability and high mechanical strength, were introduced in porous ceramic structure. The mullite whiskers were synthesized using a composition of Al2O3, flyash and MoO3. The morphologies and crystal structures of the mullite whiskers with MoO3 contents were investigated in detail. When the porous ceramic with mullite whiskers was fabricated using 20 wt% MoO3 catalyst the most uniform microstructure was obtained, and the mullite whiskers showed the highest aspect ratio of 47.03. The porosity and compressive strength of the fabricated porous ceramic were 82.12% and 0.83 MPa, respectively.
The CoCrFeMnNi high-entropy alloy (HEA), which is the most widely known HEA with a single facecentered cubic structure, has attracted significant academic attention over the past decade owing to its outstanding multifunctional performance. Recent studies have suggested that CoCrFeMnNi-type HEAs exhibit excellent printability for selective laser melting (SLM) under a wide range of process conditions. Moreover, it has been suggested that SLM can not only provide great topological freedom of design but also exhibit excellent mechanical properties by overcoming the strength–ductility trade-off via producing a hierarchical heterogeneous microstructure. In this regard, the SLM-processed CoCrFeMnNi HEA has been extensively studied to comprehensively understand the mechanisms of microstructural evolution and resulting changes in mechanical properties. In this review, recent studies on CoCrFeMnNi-type HEAs produced using SLM are discussed with respect to process-induced microstructural evolution and the relationship between hierarchical heterogeneous microstructure and mechanical properties.
The purpose of this study is to present the direction of the plan to transform the residential complex into a space that can provide an open residential environment that can lead to social communication and exchange without being closed to the urban residential environment, especially in the apartment complex environment, which is becoming more dense. As a result of the Openness analysis of the ‘Codan Shinonome Canal Court’, the overall accessibility was good in terms of space utilization, and the openness was low in terms of the spatial composition, which is a physical environment due to the dense block type. When looking at the overall openness of the Codan Sinonome complex in terms of analysis by block, the corrected openness index (C.O.I) for all six blocks was 0.245, the corrected accessibility index (C.A.I) was 1.447 and the openness composite index (O.C.I) was assessed at 1.692. This was due to the formation of high-density block-type urban dwellings and the introduction of S-shaped streets and the layout of low-rise urban support facilities and commercial facilities. The Codan Sinonome Canal Court, which is considered an “open city residence,” quantitatively confirmed that it embodies macro-space structure and human-scale space environment even in high-precision environments.
Recently, high-entropy carbides have attracted considerable attention owing to their excellent physical and chemical properties such as high hardness, fracture toughness, and conductivity. However, as an emerging class of novel materials, the synthesis methods, performance, and applications of high-entropy carbides have ample scope for further development. In this study, equiatomic (Hf-Ti-Ta-Zr-Nb)C high-entropy carbide powders have been prepared by an ultrahigh- energy ball-milling (UHEBM) process with different milling times (1, 5, 15, 30, and 60 min). Further, their refinement behavior and high-entropy synthesis potential have been investigated. With an increase in the milling time, the particle size rapidly reduces (under sub-micrometer size) and homogeneous mixing of the prepared powder is observed. The distortions in the crystal lattice, which occur as a result of the refinement process and the multicomponent effect, are found to improve the sintering, thereby notably enhancing the formation of a single-phase solid solution (high-entropy). Herein, we present a procedure for the bulk synthesis of highly pure, dense, and uniform FCC single-phase (Fm3m crystal structure) (Hf-Ti-Ta-Zr-Nb)C high-entropy carbide using a milling time of 60 min and a sintering temperature of 1,600oC.
Conventionally, metal materials are produced by subtractive manufacturing followed by melting. However, there has been an increasing interest in additive manufacturing, especially metal 3D printing technology, which is relatively inexpensive because of the absence of complicated processing steps. In this study, we focus on the effect of varying powder size on the synthesis quality, and suggest optimum process conditions for the preparation of AlCrFeNi high-entropy alloy powder. The SEM image of the as-fabricated specimens show countless, fine, as-synthesized powders. Furthermore, we have examined the phase and microstructure before and after 3D printing, and found that there are no noticeable changes in the phase or microstructure. However, it was determined that the larger the powder size, the better the Vickers hardness of the material. This study sheds light on the optimization of process conditions in the metal 3D printing field.