(A) TIRAP-derived decoy peptide hinders the TLR4-mediated down-stream signaling

조은영 Ajou University 2019 국내석사

Toll-like Receptor (TLR) signaling cascade proceed with the help of several co-receptors and adaptor proteins resulting in the activation of a protective immune response against the invading pathogens. TLR signaling pathway can be activated through the recruitment of either Myeloid Differentiation factor 88(MyD88) or Toll-Interleukin-1 receptor (TIR)-domain-containing adapter-inducing interferon-β (TRIF). TLR4, on the other hand, is endowed with the ability of activating both. During the recognition of Lipopolysaccharide (LPS) by TLR4, LPS binding protein (LBP) detaches the monomeric LPS and transfer it to CD14, which in turn exposes the captured LPS to the TLR4/MD2 complex, leading to the subsequent activation of the downstream signaling cascade and the secretion of pro-inflammatory cytokines. However, a dysregulated TLR4 response is often a hallmark of various inflammatory and autoimmune diseases, for this reason, TLRs are being actively pursued as drug targets in the treatment of immune-related disorders. Herein, we report a TIRAP-derived decoy peptide, Ajou5, which displays significant inhibitory effect on TLR4-mediated pathway. In RAW267.4 and THP-1 cells, Ajou5 inhibits the NF-κB activation monitored by SEAP assay, hinders the LPS-induced secretion of inflammatory cytokines such as TNF-α and IL-6, and inhibits the activation of Mitogen-activated protein kinases (MAPKs) and Interferon regulatory factor 3 (IRF3). Ajou5 was unable to inhibit inflammatory cytokines induced by other TLR ligands. In silico data suggested that the interaction of LBP and CD14 is similar to the interaction between Ajou5 and CD14 suggesting that Ajou5 can interrupt ligand transfer to CD14 by delaying the CD14-mediated signaling pathway.

In-bed motion sensor-based wireless network system for improved clinical data analysis

박재연 Ajou University 2020 국내석사

Recently, the advancement in data analytics including various machine learning methods lead to designing effective clinical decision support systems (CDSS) in the clinical sector. However, a CDSS including noisy clinical data can provide unhelpful (if not misleading) decision support to clinical staff as well as clinically dangerous decisions to already suffering patients. Therefore, in order to design a better and effective CDSS, such noisy data caused by patient movements and clinical protocols should be identified and filtered from the inputs in in the training dataset for CDSS development. For this purpose, we propose MediSense a system designed to identify and classify different patient motions on the bed and filter out physiological signal data points collected when patient motion occurs using sensor-based motion classification results. Essentially, MediSense can be considered as ``glasses" for the third eye in accurate-sensitive clinical domain is an intelligent embedded wireless sensing system for supporting a CDSS and consists of a motion classifier, a wireless network and localization techniques. To evaluate our system, we deploy MediSense in intensive care units (ICUs) at the Ajou University Hospital Trauma Center, a major hospital facility located in Suwon, South Korea, and evaluate its each system component's performance from real patient traces collected at these ICUs through a 4-month pilot study. Our results show that MediSense successfully classifies patient motions on the bed with >90% accuracy, shows 100% reliability in determining the locations of beds within the ICU, and each bed-attached sensor achieves a lifetime of more than 33 days, which satisfies the application-level requirements suggested by our clinical partners. Furthermore, a simple case-study with arrhythmia patient data shows that MediSense can help improve the clinical diagnosis accuracy.

(An) approach to defining the required capability of a weapon system using universal naval task list

원유재 Ajou University 2020 국내박사

The “Needs” function is the first button used to acquire a weapon system in the defense field, this indicate the force required at the mid- and long-term levels in the construction of future military forces. Thus far, Korea has created needs through “Threat-Based Planning,” which plans requirements according to clear threats. From the mid-2000s, the Korean military has focused on strengthening capabilities-based planning by benchmarking the United States Joint Capability Integration and Development System (JCIDS) and re-establishing it as a “Joint Combat Development System.” As the Korean military promoted the establishment of a Joint Combat Development System, each military had to raise a rough capabilities-based requirement. After 2019, each military was required to conduct preconception studies prior to raising the weapons system. The related laws and regulations have been revised so that each military can prepare the operational requirements document (ORD) previously prepared by the Defense Agency Program Administration (DAPA). This requires each military to strengthen its capability of planning requirements, emphasizing the ability of each military to supplement the necessity and characteristics of the weapon system and the completion of the initial requirement at the stage of raising needs. In this manner, while switching to capability-oriented requirements planning and emphasizing the user's initial activities in requirements planning, each military must clearly present the capabilities required for the weapon system to be used during planning. However, each military still raises the need to focus on the performance of a single weapon system through threat-based planning. This is because there is no method for deriving the required capability at each group level, so there is no actual capability demand. Therefore, in this thesis, the method for deriving the requirements of the weapons system centered on the capabilities of each military was studied at the stage of the capability requirement of the joint combat development system. The proposed methodology was defined as a series of processes that leads to concepts, required capabilities, attributes, and metrics, and was established as follows. First, this study focused on 'how to fight' the concept of each military's operation, which should be reflected in the concept of joint action. Upon analyzing the future environment and the mission analysis from the upper level strategic guidelines, the concept of how to perform an operation or function was materialized as a scenario. In addition, the set of activities or functions specified in the operation concept was expressed as the capability the system should have, and the derived capabilities were divided into seven classification systems in the joint capability area of the Korean military. Then, for each capability, the attribute, which is an adjective expression indicating what capability is, was selected, and the measurement criteria were set to quantitatively measure the attribute. To set metrics for each attribute, UNTL (Universal Naval Task List), which is a common task list that presents what needs to be performed by the Navy as an act of conduct during exhibitions and peacetime, was used. The verification of the methodology for defining the required capability proposed in this study was performed considering the requirements derivation, requirements planning, and systems engineering activities. First, based on the operation concept description (OCD) and operation request (ORD), the previous threat-based and capabilities-based planning requirement derivation methods proposed in this study were applied to the coastal combat ship system, respectively. The operating requirements were derived and compared. Next, in terms of planning the requirements, the methods of deriving requirements based on threats and capabilities were evaluated by an accomplished questionnaire using AHP. Third, the previous and the proposed methods were compared and evaluated by applying the Capability Maturity Model Integration (CMMI) considering the organization performing the requirements planning for the weapon system. As a result, the effectiveness of the proposed capabilities-based method for deriving the required capability was confirmed. The significance of this study supports the requirements planning capability of each military by analyzing the method of deriving the capability-centered requirement considering the activities to be performed by the military. Using the results of this study, it is possible to plan requirements focused on the needs of the users. In addition, by using the standardized language from the user's perspective, the capability to be clarified is extended to the system development stage in the future, and is expected to assist the developer in specifying system requirements.

Influence of periodontal infection upon the stage of MRONJ

홍윤표 Ajou University 2017 국내석사

Periodontal diseases and dental diseases are proved as a significant role for Medication related osteonecrosis of the jaw(MRONJ) from many studies. But there has been no study of whether periodontal disease affects not only the onset of MRONJ but also the progression of MRONJ. Thus, The aim of this study is to prove the influence of periodontal infection upon the stage of MRONJ. This study included 86 patients diagnosed with MRONJ, who visited the Department of Dentistry, Oral & Maxillofacial Surgery at Ajou University Hospital from August 2006 to September 2016. Each patient with MRONJ was staged according to the 2014 American Association of Oral and Maxillofacial Surgeons(AAOMS) MRONJ position paper. Each patient’s alveolar bone height was measured by panoramic radiography using Bjorn and Holmberg’s method. There was a significant difference in the alveolar bone height between the MRONJ groups with and without MRONJ infection as seen by the independent t-test (p = 0.004 < 0.05). From this study, Periodontal infection can affect both the risk for developing MRONJ and also the MRONJ stage.

Cyber security threat analysis model for countermeasure to new and variant threats

최슬기 Ajou University 2020 국내박사

Various researches are underway to respond to cybersecurity threats. Research on security threat modeling focuses on the definition and classification of security threats. Through security threat modeling, security threats can be accurately identified and classified, and security threat analysis can be performed more efficiently. Most of the security threat modeling currently developed identifies threats from a high-level perspective (eg, Denial of Service, Repudiation, Information disclosure etc). However, there are various techniques for generating each threat. Various techniques can be applied even if only the technology for intruding and infecting malware for generating a threat of Denial of Service is seen. As described above, from a high-level perspective, even if a security threat is identified, if a countermeasure is not actually prepared, more detailed information can be requested as a developer or an analyst. Therefore, this paper proposes a model for analyzing security threats in detail. The proposed model categorized the threat techniques that could be included into 7 categories. As a result, the procedure for continuously operating the analysis model of security threats and its effect are shown. The analysis modeling of this paper can be used to understand the trends and current status of security threats that are occurring, which can be useful for preparing countermeasures. I also presented a method that can be used to generate and verify test cases for Penetration Test.

Comparative evaluation of performance and Co₂ emissions from dual fired power plants in Ghana

Alhassan, Adam Joseph Ajou University 2020 국내석사

Electricity generation utilities in Ghana are the most focal point of attention ever since the country went into electricity supply crises. In other to meet demand there has been a sharp increase in thermal power generation. According to [1] the electricity supply industries is one of most complex technological and technical systems with several management and regulatory process and activities. The critical issue however with thermal generation is the type of fuel used as well as the environmental consequences in using different fuels for power generation. In light of this, assessing the performance of power plants is key to keeping them working efficiently and environmentally friendly for constant supply of electricity. Data Envelopment analysis (DEA) a Technical Efficiency performance assessment tool, was used to assess and compare performance of thermal power plants in Ghana by measuring and evaluating their overall Technical Efficiencies on CO2 emissions and electricity generation. This was done by placing emphasis on the most relevant inputs and output parameters. The study was therefore carried out to determine the most efficient power plant in the year 2018 based on the amount of electricity generated against CO2 emissions as desired outputs. The result showed that, KTPP and AMERI power plants were the most efficient power plants both having their relative technical efficiency score of 1 when CO2 Emission and generation were considered as desired output parameters.

Injectable gelatin-peg hydrogels for long-term delivery of dexamethasone or avastin to treat choroidal neovascularization

손주영 Ajou University 2020 국내박사

Abstract Injectable hydrogel systems have received much attention due to their versatile and tunable characteristics based on a minimal invasive technique. In a free flow state, hydrogel precursor solutions can fill up a tissue defect or target site while containing bioactive molecules, and then act as a localized therapeutic depot after physical or chemical cross-linking. A horseradish peroxidase (HRP)-catalyzed cross-linking reaction has recently received much attention as a promising approach to developing in situ forming hydrogels. For the reaction, HRP and hydrogen peroxide (H2O2) are both considered as essential prerequisites for controlling the degree and rate of cross-linking. Choroidal neovascularization (CNV) resulted by various retina and posterior segment disease particularly age‐related macular degeneration is among the main causes of blindness worldwide and in light of ongoing population ageing its prevalence is increasing specially in developed countries. As a major health concern, these ocular diseases have detrimental effects on patients’ quality of life and society economy. Considering the key role of vascular endothelium growth factor (VEGF) in the pathogenesis of CNV, Although the pathophysiology of macular edema is not yet fully understood, VEGF has been recognized as a major contributor. VEGF inhibitors have changed the paradigm of therapy and have become the standard of care during the last decade. Dexamethasone has potentially many more pathogenic targets and thus much more potential to address a therapeutic response on chronic/recalcitrant, longstanding, or severe macular edema. Avastin is a full‐length humanized antibody against all isoforms of VEGF. Avastin is widely used intravitreally in the treatment of CNV as an off‐labeled drug. Dexamethasone and Avastin have demonstrated promising effect on treatment of the disease, repetitive intravitreal injection is required due to short half‐life of the drug in vitreous. The frequency of intravitreal injection would be a leading cause in reducing patient compliance besides deleterious adverse effects including retinal detachment, subconjunctival hemorrhage and endophthalmitis. Hence, developing extended release drug delivery systems seems to be necessary to decrease the number of administrations. The main objective of this dissertation is to develop and evaluate injectable gelatin hydrogels for long term drug delivery of dexamethasone or avastin to treat choroidal neovascularization. The first work of the thesis was to prepare and characterize an injectable gelatin hydrogel via HRP catalyzed cross-linking. The gelatin hydrogels were prepared from a gelatin solution above 3 wt% in the presence of their mechanical properties such as gelation time, elastic modulus and degradation time were evaluated at different HRP, H2O2 concentration. Drug release behaviors from hydrogel were evaluated HPLC (dexamethasone) and ELISA (avastin). Through circular dichroism analysis, the structural stability of released avastin from the gelatin hydrogel was confirmed. In the cell study, the drug loaded hydrogels showed no apparent cytotoxicity. We intravitreal injected the drug loaded hydrogels into the eyes of SD rats and rabbits. The results of in vivo study demonstrated successful injection of the drug loaded hydrogel at the injected site and excellent therapeutic efficacy and pharmacokinetics.

(A) study on the optical device design based on coupled mode theory

허형준 Ajou University 2019 국내박사

Coupled-mode theory (CMT) can be modeled by properties of uncoupled resonant and/or guided mode without any complicated mathematical derivations. This provides for an intuitive grasp and a physical insight into the structural parameters for the efficient design and analysis of optical devices. The coupling between two waveguides is modeled through the formalism of a coupling-in-space and a resonant mode coupling with one or more ports in coupling-in-time. Rigorous mathematical derivations of CMT based on perturbation theory provide an accurate prospect of coupling properties. In this thesis, the author designed various optical devices, which had a high performance, using coupled mode theory. In the model of the directional coupling of a resonant mode with two ports, the broadband absorption enhancement of a monolayer graphene embedded in the center of a cavity was experimentally demonstrated by using prism coupling to meet the critical coupling conditions. The experimental results were comparable to theoretical calculations in the visible range. A compact opto-electronic coupler between the side-polished fiber and the silicon waveguide was used to enhance the graphene. It had a wavelength selectivity and a low insertion loss that were suitable for a course wavelength division multiplexer (CWDM) photodetector and was modeled as a contra-directional coupler through periodic gratings. The ultra-wideband reflector was designed by using a new approach that tailors Fano resonance between the single guided mode resonance (GMR) mode and the Fabry-Perot resonance (FPR) background mode in the high contrast grating structure (HCGs). Analysis of the new method was based on a coupled mode theory for designing reflectors provided a more intuitive understanding of the device properties in comparison to previous methods. Most of the previous investigations were conducted through modal analysis and modeling of coupled mode theory; and were verified through various numerical methods such as the transfer matrix method (TMM), the finite element method (FEM), and the rigorous coupled wave analysis (RCWA). The TMM calculated the absorption and reflectance of monolayer graphene through prism coupling into the dielectric mode. The FEM simulated the transmittance and absorption of two guided mode couplers and modal analysis. RCWA simulated the reflectance and transmittance of a wideband reflector using HCGs.

Study of improved thermoelectronic properties of inorganic materials using doping technique

김진서 Ajou University 2019 국내박사

Thermoelectricity is one of the most attractive technologies in the field of renewable energy. A material useful for thermoelectric systems is evaluated through device efficiency and power factor. Because the material's properties determine these two factors, many attentions have been paid to improve the properties, especially the Seebeck coefficient with electrical and thermal conductivities. Recently, the development of nanotechnologies and doping technologies opened a lot of opportunities for that purpose. And thus, applying these technologies to enhance the conversion efficiency of thermoelectric materials became the hot trend. Two of the most attractive thermoelectric candidates are bismuth telluride (Bi2Te3, Bi-Te) and strontium titanate (SrTiO3, STO). Bi-Te exhibits excellent thermoelectric performance at low temperatures while STO works well at high temperatures. However, there are many challenges for them to be used in practical applications. Therefore, improvement of their quality, properties, and thermoelectric performance through processing and doping techniques is targeted in this dissertation. Regarding Bi-Te, the processing method is noticed because the effects of structural engineering on the thermoelectric properties have not fully be explored. I selected a combined approach of ballmilling and spark plasma sintering (SPS) that allow tuning the structural and electrical properties of Bi-Te at low cost. Here, two types of Bi-Te materials were processed, a mixture of Bi and Te powders (i.e., “SM-Bi-Te”) and an alloy of Bi-Te (i.e., “SA-Bi-Te”). They acted as a p-type semiconductor and a meta-metal, respectively. The difference between their thermoelectric properties was examined carefully. The ZT value of SA-Bi-Te (formed at 483 K) is 1.67 times higher than that of SM-Bi-Te when measured at 300 K. The ZT value of SM-Bi-Te (formed at 533 K) is 5.05 times higher than that of SA-Bi-Te when measured at 420 K. Interestingly, I found out the effect of pre-oxidation through this 2-step approach on the increment in the electrical conductivity and the figure of merit (ZT) of Bi-Te samples in a bulk form. These are discussed in detail. Next, doping of our Bi-Te materials is carried out. A comparison of their thermoelectric performance in bulk and film forms is conducted. The dopant here is fluorine (F), which serves as an electron donor and was introduced to Bi-Te through fluorine plasma. With an increase in plasma exposure time, nonlinear dependence of ZT of the F-doped bulk samples was observed. The peak improvement of its ZT at 300 K (0.986) or at 510 K (1.061) is recorded for the samples with 40-s exposure. That is because, after 40 sec of exposure, all surface areas were covered by F ions that hindered the enetration of coming F ions. Compared to the bulk samples, the F-doped film samples have a similar tendency of the ZT dependence but their ZT is smaller at the same exposure time. Some characterizations were carried out to find a reason for this phenomenon. In general, a significant improvement of ZT of Bi-Te can be achieved through processing and doping. Regarding STO, its thermoelectric performance is tuned by the use of Nb doping (Nb:STO). In this study, I used co-sputtering to introduce Nb dopants into STO at low temperatures. Measured at low temperatures, Nb:STO and STO films, particularly their electrical conductivities, have a different temperature dependence. The insulator-to-semiconductor transition temperature of STO film is over 450K while that of Nb:STO film is just above 350K. In other words, Nb doping helps STO have a higher electrical conductivity but a lower thermal conductivity. Thereby, Nb:STO would be applicable to thermoelectric systems working at low and elevated temperatures. In addition, Nb:STO films exhibit high thermal stability measured up to 973 K. It renders Nb:STO as a potential candidate for thermoelectric applications at elevated and high temperatures. In general, the optimization of thermoelectric materials is critical to expanding their potential for practical applications. My studies revealed the importance and advantages of the processing steps of thermoelectric materials regarding tuning their structural properties. Furthermore, our findings indicated the advantages and disadvantages of doping for Bi-Te and STO materials. Altogether, this dissertation presents the effects of processing and doping on the thermoelectric materials, and they are a vision for developing promising thermoelectric materials in the future.

How to enhance divergent thinking by priming the hemisphericity using block design

Ikram, Madiha Ajou University 2016 국내석사

Following the assumption of corresponding gravity of the right hemisphere (RH) in divergent thinking as previously explained that there are many ways to measure divergent thinking. The following study is intended to investigate whether we can enhance divergent thinking (Creative ability) by activating right hemisphere (RH) using block design of Kwais-IV. Practicing block design of Kwais-IV can activate right hemisphere (RH) and we can scrutinized the probability to boost divergent thinking by artificially activating the RH using block design of Kwais-IV. Following block design, participants pursue the Torrance Test.The results shows that manipulated group who experience the block design for about 20minutes attained significant higher score in Elaboration, a subscale of Torrance test compared to those who did not experience any manipulation, thus no activation of right hemisphere(RH). This results explains that through a simple task in short time so that activating the right hemisphere (RH) can enhance the divergent thinking. Therefore, the inclination from hemisphericity to right hemisphere (RH) through visuospatial abilities will cause remarkable impact on the fallout of creative thinking processes i.e. divergent thinking well illustrated in this study. If we neglect the peculiar mechanism involved, this practice of simple task (block design) has the likelihood to serve as a remedial to increase creative thinking, motivation and skills for creative achievement in such high-tech smart world.