A Survey of System Architectures, Privacy Preservation, and Main Research Challenges on Location-Based Services

( Mulugeta K. Tefera ),( Xiaolong Yang ),( Qifu Tyler Sun ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.6

Location-based services (LBSs) have become popular in recent years due to the ever-increasing usage of smart mobile devices and mobile applications through networks. Although LBS application provides great benefits to mobile users, it also raises a sever privacy concern of users due to the untrusted service providers. In the lack of privacy enhancing mechanisms, most applications of the LBS may discourage the user’s acceptance of location services in general, and endanger the user’s privacy in particular. Therefore, it is a great interest to discuss on the recent privacy-preserving mechanisms in LBSs. Many existing location-privacy protection-mechanisms (LPPMs) make great efforts to increase the attacker’s uncertainty on the user’s actual whereabouts by generating a multiple of fake-locations together with user’s actual positions. In this survey, we present a study and analysis of existing LPPMs and the state-of-art privacy measures in service quality aware LBS applications. We first study the general architecture of privacy qualification system for LBSs by surveying the existing framework and outlining its main feature components. We then give an overview of the basic privacy requirements to be considered in the design and evaluation of LPPMs. Furthermore, we discuss the classification and countermeasure solutions of existing LPPMs for mitigating the current LBS privacy protection challenges. These classifications include anonymization, obfuscation, and an encryption-based technique, as well as the combination of them is called a hybrid mechanism. Finally, we discuss several open issues and research challenges based on the latest progresses for on-going LBS and location privacy research.

The Determination of Temperature and Humidity Sensitivity Coefficients of Torque Transducers using Seasonal Climatic Changes of Ambient Conditions in the Laboratory

무루게타(Mulugeta Derebew),김민석(Min Seok Kim),박연규(Yon Kyu Park),이호영(Ho Young Lee) Korean Society for Precision Engineering 2015 한국정밀공학회지 Vol.32 No.2

This paper presents a new method to determine sensitivity coefficients of temperature and humidity of torque transducers by using a natural and seasonal variation of ambient conditions at the laboratory. We had measured the sensitivities of the torque transducers over almost one year using the KRISS 2 kN m torque standard machine. The sensitivity data acquired at various ambient conditions were processed using our measurement model to extract the sensitivity coefficients of temperature and humidity simultaneously with high precision. A comparison with a previous method using an environmental control chamber was carried out to test the feasibility of using our new method. Two results agreed within the uncertainty. We revealed that the torque measuring errors could be 8 times higher than the measurement and calibration capability of KRISS torque standard machine if the sensitivity changes due to the temperature and humidity are not properly corrected during a calibration.

Effect of Laser Induced Groove Morphology on the Wetting Property and Electrochemical Performance

Berhe Mulugeta Gebrekiros,J. Shin(신재근),D. Lee(이동경) Korean Society for Precision Engineering 2022 한국정밀공학회 학술발표대회 논문집 Vol.2022 No.5

에티오피아의 Dabus 유역의 SWAT 모형을 이용한 토지이용 변화에 따른 유출 및 퇴적물 모델링

무루게다메레세 ( Mulugeta Melese ),남원호 ( Won-ho Nam ) 한국농공학회 2019 한국농공학회 학술대회초록집 Vol.2019 No.-

Land use/land cover (LULC) change is conversion of one cover type to another and/or modification a change within one land use category and it is an undeniable global trend. This study was conducted in Dabus watershed in west Ethiopia where there is high soil erosion which aggravated by LULC change. The objectives of this study were to examine the LULC dynamics in the Dabus watershed in the last three decades, to identify the main drivers of LULC change in the watershed, to assess the soil erosion risk and determine sedimentation to the watershed by using hydrological modelling and prioritize land management intervention in the watershed. The study will utilize different type of data including Digital Elevation Model (DEM), soil map, Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) satellite and weather data. Three decades, Landsat TM/ETM, 1986, 2005 and 2017 will use for generating land use land cover map for study area and detecting the change between these three time periods and simulated by the Soil and Water Assessment Tool (SWAT) compared with measured values. The SWAT model will evaluate through sensitivity analysis calibration and validation. Finally see the results of land use land cover change dynamics on runoff and sediment yield on the Dabus sub basin. Prioritizing sub-watersheds which are, first stage and second stage need urgent solutions. Therefore, appropriate land use planning, physical conservation mechanisms (Terracing and contour ploughing) and biological conservation (Afforestation and area closure) should be implemented.

A Textile-Based MWCNT-Coated Stretch Sensor for Body Size Measurements

Mihret Mulugeta,Jaehwan Ko,Young Soo Yoon,Sun Hee Kim 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.8

In this study, a textile-based stretch sensor with a polymer/conductor/polymer structure was fabricated using a paste of multiwalled carbon nanotubes (MWCNTs) as the conductive material. A simple and practical method that integrates with the manufacturing methods employed in the garment industry was designed. The stretch sensor showed varying performance depending on the anchoring points, that is, the stretched part. When only the sensor was fixed, the linearity of the resistance and the sensitivity were good, though the durability was low. On the contrary, when the elastic band was fixed, the linearity of the resistance and sensitivity were low, and the durability was good. To verify whether the manufactured stretch sensor can be applied to body size measurement garments, we fabricated and evaluated a belt by measuring the waist and the hip sizes of 10 people. The strain spanned a wide range from 3% to 85%, and the resistance maintained its linearity. The results of this study indicate that the elastic difference between the stretch sensor and the surrounding fabric can lead to problems; hence, we suggest that materials and design be selected accordingly.

A Comparative Study on the Wettability of Unstructured and Structured LiFePO4 during Nanosecond Pulsed Fiber Laser

M. G, Berhe(Mulugeta Gebrekiros Berhe),Y. Seo(서영진),N. L. Trinh(Trinh Ngoc Lanh),D. Park(박동규),M. M. Lian(Mang Muan Lian),S. Baek(백승은),S. Han(한시은),S. Jeon(전수빈),J. Kim(김준기),D. Lee(이동경) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.5월

Preparation of polyethylene terephthalate foams at different saturation temperatures using dual methods of supercritical batch foaming

권동의,Mulugeta G. Aregay,박병규,이윤우 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.12

Polyethylene terephthalate (PET) foams were prepared at different saturation temperatures using two supercritical foaming methods. The average cell size, cell number density, and porosity of PET foams obtained using each foaming method were compared. The crystallinity of the PET samples after the saturation step in the two-step foaming process was measured to observe the CO2-induced crystallization. The crystallinity of PET according to the saturation temperature led to a variation in cell size in the two-step foaming. In contrast, the melting of crystals with the increase in the temperature affected the cell number density of the polymeric foam prepared by one-step foaming method. The influence of the PET crystals on the cell nucleation or cell growth in each foaming method was studied from these results.

Special Review : Role of Corticotropin-releasing Factor Signaling in Stress-related Alterations of Colonic Motility and Hyperalgesia

( Yvette Tache ),( Mulugeta Million ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.1

The corticotropin-releasing factor (CRF) signaling systems encompass CRF and the structurally related peptide urocortin (Ucn) 1, 2, and 3 along with 2 G-protein coupled receptors, CRF1 and CRF2. CRF binds with high and moderate affinity to CRF1 and CRF2 receptors, respectively while Ucn1 is a high-affinity agonist at both receptors, and Ucn2 and Ucn3 are selective CRF2 agonists. The CRF systems are expressed in both the brain and the colon at the gene and protein levels. Experimental studies established that the activation of CRF1 pathway in the brain or the colon recaptures cardinal features of diarrhea predominant irritable bowel syndrome (IBS) (stimulation of colonic motility, activation of mast cells and serotonin, defecation/watery diarrhea, and visceral hyperalgesia). Conversely, selective CRF1 antagonists or CRF1/CRF2 antagonists, abolished or reduced exogenous CRF and stress-induced stimulation of colonic motility, defecation, diarrhea and colonic mast cell activation and visceral hyperalgesia to colorectal distention. By contrast, the CRF2 signaling in the colon dampened the CRF1 mediated stimulation of colonic motor function and visceral hyperalgesia. These data provide a conceptual framework that sustained activation of the CRF1 system at central and/or peripheral sites may be one of the underlying basis of IBS-diarrhea symptoms. While targeting these mechanisms by CRF1 antagonists provided a relevant novel therapeutic venue, so far these promising preclinical data have not translated into therapeutic use of CRF1 antagonists. Whether the existing or newly developed CRF1 antagonists will progress to therapeutic benefits for stress-sensitive diseases including IBS for a subset of patients is still a work in progress.

Diagnosis and Risk Factors of Advantage Cancers in Ethiopia

Samrawit Solomon,Wudeneh Mulugeta 대한암예방학회 2019 Journal of cancer prevention Vol.24 No.3

Background: Cancer is one of the leading causes of morbidity and mortality worldwide. Yet, limited is known about patterns of cancer and risk factors for advanced stage cancers in Ethiopia. Methods: A cross-sectional study was conducted on 919 patients with biopsy-confirmed cancers at Tikur Anbessa Hospital in Ethiopia, 2010 to 2014. Pearson chi-square test, t-test, analysis of variance and multivariate logistic regression analyses were performed. Results: The majority of the patients were females (72.4%). The commonest malignancies among males were bone and soft tissue (16.5%), colorectal (12.2%), and esophageal (9.1%). Among females, the most common cancers were cervical (39.7%), breast (18.3%), and ovarian (7.1%); of these, 41.7%, 59.0%, and 42.6% were diagnosed at advanced stages, respectively. Females had more advanced stage cancers at diagnosis than males (37.6% vs. 24.8%, P < 0.01). Among males, 46.7% of prostate and 29.0% of colorectal cancers were in advanced stages at the time of diagnosis. Delay in presentation from onset of symptoms was associated with advanced cancer among females (OR = 3.21; 95% CI = 1.69-6.10). Prostate cancer among males (OR = 5.22; 95% CI = 1.26-21.60) and breast cancer among females (OR = 1.93; 95% CI = 1.23-3.03) were more likely to be diagnosed at advanced stages. Conclusions: Cancers with effective screening tests are common in Ethiopia and significant proportions of these were diagnosed at advanced stages, typically several months after onset of symptoms. Timely access to preventive care along with effective educational and screening strategies is needed in Ethiopia for early detection and treatment of common malignancies, such as cervical, breast and colorectal cancers. (J Cancer Prev 2019;24:163-172)

Professed vis-à-vis Enacted Knowledge: Topic-Specific Pedagogical Content Knowledge of University Mathematics Teachers

Yosef Kasa,Solomon Areaya,Mulugeta Woldemichael 대한수학교육학회 2023 수학교육학연구 Vol.33 No.2

This study aimed to determine and observe the topic-specific pedagogical content knowledge of university mathematics teachers before and during limit and continuity concept instruction, and compare the teachers’ perceptions of their teaching to what happened in their classrooms using the case study method. The study involved five university mathematics teachers who teach ‘Applied Mathematics I’ to pre-engineering students at Assosa University, Ethiopia. Classroom observation sessions and pre-lesson teacher interviews were used as data sources. The data were analyzed by identifying common themes in each of the knowledge components prior to and during the lesson, and then by comparing the two phases. The findings from the teacher cases provided detailed contextual information and revealed knowledge manifestations in their lesson design and actual teaching processes. The study’s findings revealed that teachers had a good understanding of topic-specific pedagogical content knowledge components prior to the lesson, but did not demonstrate most of these in their actual teaching of limit and continuity; their reported and enacted knowledge differed. According to this study, individual teachers varied in their implementation of what they had mentioned about various components of topic-specific pedagogical content knowledge. The study proposes that understanding teachers’ knowledge during the lesson design phase and actual teaching could help fill the gap as a means of professional development, and thereby, improve pre-engineering students’ mathematics learning.