• International Journal of Internet, Broadcasting and Communication
• /
• v.14 no.3
• /
• pp.249-257
• /
• 2022

In recent years, if we order food by easily accessing the online market with our smartphone, we can receive the product in a fresh state at dawn the next day. Cold chain is an industry that can create high added value because it has both the characteristics of general logistics and sensitivity to temperature. Based on the electrical specifications derived from the reefer container capacity requirement investigation, we proved that power supply to up to 33 reefer containers can be made by using three additional auxiliary power supplies which are applied for freight trains in Korea. In this paper, we conducted a research on a design of power supply system for freight train reefer container based on simulation as a basic research necessary for low-temperature distribution and cold chain construction based on the reefer container railroad. Consequently, the simulation was conducted using the three-phase inverter diagram in PSIM and the SVPWM (3-harmonic injection method) control technique, and it was verified that the required power voltage was satisfied with 622V_dc, which is lower than the input voltage of general SPWM of 718V_dc. The details of this paper could be used as a foundational study for constructing cold chains based on a reefer container dedicated to freight trains in the future.

• Health Policy and Management
• /
• v.33 no.1
• /
• pp.29-39
• /
• 2023

Background: Breaking the chain of disease transmission from overseas is necessary to control new infectious diseases such as coronavirus disease 2019 effectively. In this study, we developed a mobile app called Self-Symptom Checker (SSC) to monitor the health of inbound travelers. Methods: SSC was developed for general users and administrators. The functions of SSC include non-repudiation using QR (quick response) codes, monitoring fever and respiratory symptoms, and requiring persons showing symptoms to undergo polymerase chain reaction tests at nearby screening stations following a review of reported symptoms by the Korea Disease Control and Prevention Agency, as well as making phone calls, via artificial intelligence or public health personnel, to individuals who have not entered symptoms to provide the necessary information. Results: From February 12 to March 27, 2020, 165,000 people who were subjected to the special entry procedure installed SSC. The expected number of public health officers and related resources needed per day would be 800 if only the phone was used to perform symptom monitoring during the above period. Conclusion: By applying SSC, more effective symptom monitoring was possible. The daily average number of health officers decreased to 100, or 13% of the initial estimate. SSC reduces the work burden on public healthcare personnel. SSC is an electronic solution conceived in response to health questionnaires completed by inbound travelers specified in the World Health Organization International Health Regulations as a requirement in the event of a pandemic.

• Korean Journal of Computational Design and Engineering
• /
• v.17 no.6
• /
• pp.398-408
• /
• 2012

This paper investigates the tolerance stack-up in a commercial sliding-type mobile phone model developed by a Korean electronics company, with focus on the dimensional quality of the gap between the sliding top and the main body. The tolerance analysis in this study is done using a commercial software package, which runs Monte Carlo simulations to produce the statistical distributions of the gap size at desired locations. Such an analysis revealed that the original design did not yield the desired dimensional quality of the gap. Through a series of systematic analyses and syntheses, an improved design is proposed for the nominal dimensions and tolerances of selected features of the parts. The proposed design was validated, through tolerance analysis simulation, to meet the desired requirement of the gap quality.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.68-73
• /
• 2009

As various haptic algorithms and haptic equipments have developed, the computer simulation includes the haptic simulation. Basically, the haptic simulation requires very fast refresh rate approximately 1000 Hz. The traditional haptic simulations have satisfied that requirement by simplifying the target model. In soft body simulation, simplifying the deformation is not good because the visual feedback is important. Separating haptic model from deformable model can be solution of that problem. However, the user may feel a subtle distiction because the relationship between two models are not clear. In this paper, we propose the hybrid model to manipulate haptic rendering and deformation and define the relationship between two models.

• Microbiology and Biotechnology Letters
• /
• v.19 no.2
• /
• pp.153-157
• /
• 1991

Intracellular enzymes of an extreme halophilic bacterium, Halobacterium sp. HE10, isolated from a saltern in Korea was investigated. The membrane-bound enzyme, NADH dehydrogenase, involved in electron transport system was stimulated by the addition of 2.0 M NaCl. The respiratory enzyme activities such as NADH oxidase and NADH dehydrogenase was decreased on removal of $Na^+$ ion and restored when replaced with cations like $K^+$, $Li^+$and $NH_{4}^{+}$ ions. Furthermore, their activities were affected by the anions such like carbonate, acetate, sulfate, chloride and nitrate at the presence of $Na^+$ion. Lactate dehydrogenase activity was highest at the asturated solution of NaCl and isocitrate dehydrogenase activity was a maximum level at 1.0 M NaCl. These results suggested that the enzyme activites of the respiratory chain in Halobacterium sp. EH10 was stimulated by the presence of $Na^+$ ion.

• KSTLE International Journal
• /
• v.6 no.1
• /
• pp.28-32
• /
• 2005

The electrorheoloRical (ER) fluids are composed of a colloidal dispersion of polarizable particles in insulating oil, and it's the rheological property changes by the applied electric field. These changed are reversible and occur fast within a fewmilliseconds. The ER properties of the ER fluid such as increment of viscosity and yield stress come from the particle chain structure induced by electric fleld. When formulating the ER fluid for a speciflc application, some requirement must besatisfled, which are high yield stress under electric field, rapid response, and dispersion stability. While this characteristic makes valuable ER fluids in valious industrial applications, their lung term and quiescent application has been limited because ofproblems with particle sedimentation. In an effort to overcome sedimentation problem of ER fluids, the anhydrous ER materials of monodispersed hollow polyaniline (PANI) and adipate derivative respectively with submicron-sized suspension providing wide operating temperature range and other advantage were synthesized in a four-step procedure. The ER fluidswere characterized by FT-lR, TGA, DLS, SEM, and TEM. Stability of the suspensions was examined by an UV spectroscopy.The rheological and electrical properties of the suspension were investigated Couette-type rheometer with a high voltagegenerator, current density, and conductivity. And the behavior of ER suspensions was observed by a video camera attached toan optical microscope under 3kV/mm. The suspensions showed good ER properties, durability, and particle dispersion.

• Herbal Formula Science
• /
• v.15 no.2
• /
• pp.119-126
• /
• 2007

Objectives: This study presents observation of microorganism such as total aerobic bacteria, total fungus, E. coli, Pseudonomas aerugjnosa, Staphylococcus aureus, and Salmonella typhimurium in herbal decoction manufactured by Korean medical clinic. Methods: We examined to observe microorganism using the requirements for the experimental methods recommended by FDA. For the identification, we observed microscopic methods and carried out polymerase chain reaction (PCR) and DNA purification. The purified DNA samples were analyzed by DNA sequencer. As compared with NCBI database. the results were identified by sequences similarity. Results and conclusion: 26 (55%) of 46 decoctions observed positive for microbial test. 12 (46 %) of 26 positive decoctions exceed requirement of microbial limit test. These microbial colony identified genus of Bacillus using microscopic and DNA sequencing methods.

• 한국HCI학회:학술대회논문집
• /
• 2008.02b
• /
• pp.634-639
• /
• 2008

사회적 컴퓨팅(social computing)의 현상이 Web 2.0 공급사슬(supply chain)의 변화관점에서 새로운 변화의 단계를 맞이하고 있다. Web 2.0 플랫폼을 어떤 형태로 기업 활동에 활용할 것인가 하는 문제제기에 대하여 다양한 기업 활동의 변화사례가 발견되고 있다. 본 논문은 그와 같은 다양한 Web 2.0 환경 확산에 대한 기업 활동의 변화현상 중에서 Web 2.0 플랫폼을 기반으로 한 신제품개발(New Product Development) 사례연구를 통하여 진행한 결과를 반영하였다. 신제품 개발을 위한 플랫폼으로서 Web 2.0 의 협업적 환경을 설계하게 될 경우, 고객의 내재적 요구사항(latent requirement)이 제품개발에 효과적으로 반영될 수 있도록 하는 절차(process)가 기존의 제품개발방법론과 연관되어, 어떤 형태로 적용되고 개선되어 발전될 수 있는가에 대한 경험적 사례를 사례연구방법의 탐험적 경향을 활용하여 살펴보았다. 본 논문에서 다루어졌던 사례는 Web 2.0 플랫폼을 기반으로 사용자 창작 콘텐츠(User Created Content)를 생산하고 증가된 연세대학교 UCC의 양적 팽창에 의해서 수익모델이 발생하는 전형적인 Web 2.0 비즈니스 모델의 구조를 보여주는 경우였다. 본 연구를 통해서 사용자의 내재적 요구사향을 Web 2.0 기술특성을 통해서 참여적 사용자, 혹은 사용자 디자이너들의 적극적인 활동에 의해서 개선 및 구현해 가는 과정을 구체적 개발방법론의 틀로서 정착하려는 시도를 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.8
• /
• pp.3328-3349
• /
• 2020

With rapid development of ubiquitous computing and location-based services (LBSs), human trajectory data and associated activities are increasingly easily recorded. Inappropriately publishing trajectory data may leak users' privacy. Therefore, we study publishing trajectory data while preserving privacy, denoted privacy-preserving activity trajectories publishing (PPATP). We propose S-PPATP to solve this problem. S-PPATP comprises three steps: modeling, algorithm design and algorithm adjustment. During modeling, two user models describe users' behaviors: one based on a Markov chain and the other based on the hidden Markov model. We assume a potential adversary who intends to infer users' privacy, defined as a set of sensitive information. An adversary model is then proposed to define the adversary's background knowledge and inference method. Additionally, privacy requirements and a data quality metric are defined for assessment. During algorithm design, we propose two publishing algorithms corresponding to the user models and prove that both algorithms satisfy the privacy requirement. Then, we perform a comparative analysis on utility, efficiency and speedup techniques. Finally, we evaluate our algorithms through experiments on several datasets. The experiment results verify that our proposed algorithms preserve users' privay. We also test utility and discuss the privacy-utility tradeoff that real-world data publishers may face.

• Journal of Korean Society for Quality Management
• /
• v.39 no.4
• /
• pp.516-526
• /
• 2011

The AS9100 standard builds upon the ISO 9001:2000 quality management system requirements(in their entirety) and defines additional quality management system requirements for the aerospace industry. The 9100 standard on quality management system requirements is intended to be used at all levels of the supplier chain. The International Aerospace Quality Group has released a revision to 9100 for the aviation, space and defense industries. This change aims at improvement on quality, schedule and cost performance by adopting new requirements based on stakeholders' needs. This paper is to review how the AS9100 QMS Requirement has been established and improved, and to communicate the significant changes from AS9100, Rev. B to Rev. C focusing on reasons for revisions. The proposed schedule and considerations on the transition of the changes to Rev. C are also dealt with in this paper.